Sunday, 28 June 2026

On This Day in Math - June 28

   


In my opinion, a mathematician, in so far as he is a mathematician, need not preoccupy himself with philosophy -- an opinion, moreover, which has been expressed by many philosophers.

Henri Lebesgue

The 179th day of the year

179 is a "Knockout Prime" of the form K(3,2) since 17, 19, and 79 are all prime.

179 is an emirp, a prime whose reversal, 971 is also prime, and the combination sum and product 179 * 971 + 179 + 971=174959 is also an emirp.

1793 has all odd digits, 5735339. *Derek Orr

179 is a prime whose square, 32041, has one each of the digits from 0 to 4.


179 is an emirp, a prime whose reversal, 971 is also prime, and the combination sum and product 179 * 971 + 179 + 971=174959 is also an emirp.

179 = (17 * 9) + (17 + 9)

A winning solution to the 15-hole triangular peg solitaire game is: (4,1), (6,4), (15,6), (3,10), (13,6), (11,13), (14,12), (12,5), (10,3), (7,2), (1,4), (4,6), (6,1). The term (x,y) means move the peg in hole x to y. Not only does this solution leave the final peg in the original empty hole, but the sum of the peg holes in the solution is prime. But not just any prime, it is 179.

Between the beginning and the 179th digit of π, an equal number of five different decimal digits occur (there are 18 each of the digits 0, 3, 4, 5, and 9). Mike Keith conjectures this to be the last digit of π for which this happens (there are no others up to 10^9 digits). *Prime Curios

1/179 has a repeating patter of 178 digits, called a full repetend prime.

179 is a strictly non-palindromic number. It is not a palindromic number in any base.*Wikipedia


More Math Facts for every year date here



EVENTS

1451 Sort of the American version of the Medes and Lydians. The Seneca and Mohawk tribes were preparing for war when a total solar eclipse swept over both their camps late in the afternoon of this early summer day. Both immediately sued for peace. (ref. DB 6/97: "A star Called the Sun" by George Gamow). *NSEC

This Total, or near total eclipse is thought by many to have marked the beginning of the Haudenosaunee (Iroquois) Confederacy, the oldest living democracy in North America and possibly on Earth. American democracy is said to have been modeled upon the democratic ideals of the Iroquois Confederacy, which originally consisted of five nations (Mohawk, Oneida, Onondaga, Cayuga and Seneca). *Earth Sky

Iroquois, one of the historical figures of the Maisonneuve Monument, by Louis-Philippe Hébert, 1895, Place d’Armes, Montreal. Photo via Wikimedia Commons.




1489 Last total solar eclipse on Easter Island before the one on 11 July 2012. The next will be on 25 February 2324. Ref. More Mathematical Astronomical Morsels by Jean Meeus; Willmann-Bell, 2002. *NSEC


1751 The first volume of Diderot’s and d’Alembert’s Encyclopedie appeared. See Hawkins, Jean d’Alembert p. 69.*VFR

Between 1751 and 1780 French philosopher, art critic, and writer Denis Diderot and French mathematician, mechanician, physicist and philosopher Jean le Rond d'Alembert edited and wrote portions of the Encyclopédie ou dictionnaire des sciencesOffsite Link, des arts et des métiers, par une société‚ de gens de lettres in 17 folio volumes of text plus 11 folio volumes (i.e., 10 volumes in 11) of plates. This is usually described as the first encyclopedia ever printed.  




1774 A Bill passed by Parliament included a clause to pay John Harrison for inventing a Timekeeper for finding Longitude at Sea. H5 was put on trial by the King himself in 1772, and performed superbly. The Board of Longitude, however, had refused to recognize the results of this trial, so John and William petitioned Parliament. They were finally awarded £8750 by this Act of Parliament. Perhaps more importantly, John Harrison was finally recognized as having solved the longitude problem. *Nat. Maritime Museum ‏@NMMGreenwich, *ticktocktony.com




1832 the first American case of a cholera epidemic was reported in New York City. Previously, Europe and the Americas were unaffected by the First Cholera pandemic of 1817 when cholera, long endemic to the Indian subcontinent, spread to Arabia, Syria, and southern Russia. This abated in the early 1820's, but a new cholera cycle began in 1826. It invaded the British Isles in Oct 1831. Canada was struck shortly before cholera reached New York. Cholera was a horrible disease, spread through fouled water. Its victims died after hours of cramps, diarrhea, and vomiting. Crowded into unsanitary slums, the poor suffered most. Many of the city's elite fled to the countryside. In America, the disease's hold broke by Dec 1832.*TIS


1884 Sonya Kovalevskaya officially appointed extraordinary professor at Stockholm University, thus becoming Sweden's first female professor, and the world's first female professor of mathematics.  [The Mathematical Intelligencer, vol. 6, no. 1, p. 29; *VFR ]

Following his first meeting with Sofia in 1876, Gösta Mittag-Leffler said of Sofia that, I understand perfectly why Weierstrass regards her as the most talented of his students. It was the fact that he held her in such high regard which made him determined to find a suitable position for her. During his time at the University of Hilsingfors he had tried to find a place for her on the faculty yet was unsuccessful not due to the fact that she was a woman, but due to the fact that she was Russian with what those in charge of the institution regarded as radical beliefs. On taking up his place as the head of mathematics at the recently founded Stockholm University however, he was to find himself in a position where he could actually offer her a job. From the very beginning Stockholm University offered great academic freedoms to those students in attendance. Classes were open to both sexes, and there were no examinations until a student decided that they wished to sit for a degree. Mittag-Leffler was to use his considerable diplomatic and organisational skills to offer Sofia a temporary position before those who opposed such a move had the chance to gather their forces. She readily accepted this position as a sub-professor without pay or official affiliation to the university, and hoped that by doing so she would open up the profession to women throughout Europe.

Sophia wrote to Mittag-Leffler at around this time that, Weierstrass is much more anxious than I for my appointment. It is certainly true that he wanted to see her flourish in her role as a mathematician and that this was what they both felt should be the next step on her path. He did however urge her to take the time to prepare properly for her new role knowing that her work would be subject to far more rigorous scrutiny than that of her male counterparts. Her arrival in Stockholm was thus delayed until November 1883, when her appointment made the front page of the newspapers. *SAU





1949 Wolfgang Pauli writes to Carl Jung to with theories of the "Pauli effect", which Jung described as synchronicity. Pauli was famous among his colleagues for the numerous instances in which demonstrations involving equipment suffered technical problems only when he was present. He was actually banned from the laboratory of Otto Sturn a frequent dinner companion. Pauli and Jung both believed there was an effect, and tried to explain it. In this letter Pauli uses an example from the I-ching, the Chinese book of changes, to describe his thoughts on the effect. *Charles P. Enz, No Time to be Brief: A Scientific Biography of Wolfgang Pauli,


In 1958, the Mackinac Bridge, the world longest suspension bridge, was dedicated. Ceremonies began on 24 Jun with the first "Governor's Walk" across the bridge. (It had opened to traffic on 1 Nov 1957.) This bridge joins the upper and lower peninsulas of the state of Michigan, reducing the crossing time, from a couple of hours, to just 10 minutes. Ceremonial groundbreaking took place at the St. Ignace end of the bridge on 7 May 1954, and on the opposite shore at Mackinaw City the next day. Meanwhile caissons and superstructures were assembled as far away as Indiana, Pennsylvania and Ohio. Including approaches, the total length is 26,444-ft, needing 34 bridge support foundations. The main span is 3,800-ft long. *TIS




1979 New Scientist publishes "The Man Who Invented Black Holes,"  about a description of black holes from 1783 by English natural philosopher John Michell presented to the Royal Society in November, :

"Let us now suppose the particles of light to be attracted in the same manner as all other bodies with which we are acquainted; that is, by forces bearing the same proportion to their vis inertiae (or mass), of which there can be no reasonable doubt, gravitation being, as far as we know, or having any reason to believe, an universal law of nature. ... [I]f the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1, a body falling from an infinite height towards it, would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertiae, with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity."  Futility closet 

He was an English natural philosopher and clergyman who provided pioneering insights into a wide range of scientific fields including astronomy, geology, optics, and gravitation. Considered "one of the greatest unsung scientists of all time", he is the first person known to have proposed the existence of stellar bodies comparable to black holes, and the first to have suggested that earthquakes travelled in (seismic) waves. Recognizing that double stars were a product of mutual gravitation, he was the first to apply statistics to the study of the cosmos. He invented an apparatus to measure the mass of the Earth, and explained how to manufacture an artificial magnet. He has been called the father both of seismology and of magnetometry. *Wik

Michell's torsion balance, used in
the Cavendish experiment, *Wik




2009 Stephen Hawking gave a party for time travelers at 12:00 UT on this day. He did not announce the event until after it was over, and it appears that no one else cared to attend. Below is the invitation, so if you missed it up until now, it's not to late to choose not to attend. (So much for free will)



*daily Mail online


2011 "6.28" has become popular as Tau day with many people who think 2 pi (or 6.28...) is more appropriate, or just a nice addition to Pi-day, on March 14 (or 3.14... )



Births




1858 Alice Lee (1858–1939) was a British statistician and mathematician, one of the first women to graduate from London University. She was awarded a PhD in 1901. She worked with Karl Pearson from 1892. She was notable for demonstrating that the correlation between cranial capacity and gender was not a sign of greater intelligence in men compared to women.

From about 1895 Lee attended Karl Pearson's statistics lectures at University College London and became interested in his application of statistical methods to evolutionary biology. Under his direction she studied for an advanced degree. Her research topic was an investigation of variation in cranial capacity in humans and its correlation with intellectual ability. Lee courted controversy with her first published paper on the subject in 1901 A study of the correlation of the human skull. She examined three groups - women students from Bedford College, male faculty at University College, and a collection of distinguished male anatomists. The study demonstrated that there was no correlation between skull size and intelligence. Through a formula Lee calculated the cranial capacity from the anatomical measurements. The individuals in the groups were ranked in order of decreasing skull size, and identified by name. The dissertation was completed in 1899 and the findings caused considerable controversy. It was then an accepted theory in craniology that brain power increased with size, hence skull capacity was a measure of mental ability. As a consequence it was believed that men, who generally had larger heads than women, were mentally superior. Lee's findings shed doubt on that belief. Furthermore, one of the examiners of her dissertation was an anatomist with a low ranking in the skull capacity table of her study. Lee's study drew considerable criticism from her thesis examiners and from eugenicist Francis Galton, who questioned the originality and the scientific quality of her work. It was through Pearson's intervention that Lee was finally awarded a PhD in 1901. The following year Pearson published two papers which answered to the criticism that had been levelled at the findings of Lee's study. As there were no effective challenges this work was soon accepted. *Wik



1875 Henri Lebesgue (June 28, 1875 – July 26, 1941) He introduced the concept of Lebesgue Measure, a device for measuring the ‘length’ of complicated sets of points on the line, and so is known as the father of modern integration theory. *VFR French mathematician whose generalization of the Riemann integral revolutionized the field of integration. He was maître de conférences (lecture master) at the University of Rennes until 1906, when he went to Poitiers, first as chargé de cours (assistant lecturer) of the faculty of sciences and later as...*TIS





1894 Einar Hille (28 June 1894 – 12 February 1980) born. In the preface of his Analytic Function Theory (1959) he wrote “It is my hope that students of this book may come to respect the historical continuity of the subject.” More authors should include historical footnotes as good as those in this book.*VFR Hille's main work was on integral equations, differential equations, special functions, Dirichlet series and Fourier series. Later in his career his interests turned more towards functional analysis. His name persists among others in the Hille–Yosida theorem. *Wik




1906  Maria Goeppert Mayer (June 28, 1906 – February 20, 1972) was a German-born American theoretical physicist, and Nobel laureate in Physics for proposing the nuclear shell model of the atomic nucleus. She was the second woman to win a Nobel Prize in physics, the first being Marie Curie. In 1986, the Maria Goeppert-Mayer Award for early-career women physicists was established in her honor.

*Wik



1920 Nicolaas Hendrik "Nico" Kuiper (28 June 1920, Rotterdam - 12 December 1994, Utrecht) was a Dutch mathematician, known for Kuiper's test and proving Kuiper's theorem. He also contributed to the Nash embedding theorem.
Kuiper completed his Ph.D. in differential geometry from the University of Leiden in 1946 under the supervision of Willem van der Woude.
He served as director of the Institut des Hautes Études Scientifiques from 1971 to 1985.*Wik



Gloria C. Gilmer (née Ford; June 28, 1928 – August 25, 2021) was an American mathematician and educator, notable for being the first African American woman to publish a non-PhD thesis.



1934 Michael Artin (German: [ˈaʁtiːn]; born 28 June 1934) is an American mathematician and a professor emeritus in the Massachusetts Institute of Technology Mathematics Department, known for his contributions to algebraic geometry.

Artin was born in Hamburg, Germany, and brought up in Indiana. His parents were Natalia Naumovna Jasny (Natascha) and Emil Artin, preeminent algebraist of the 20th century of Armenian descent. Artin's parents left Germany in 1937, because his mother's father was Jewish. His elder sister is Karin Tate, who was married to mathematician John Tate until the late 1980s.

In the early 1960s, Artin spent time at the IHÉS in France, contributing to the SGA4 volumes of the Séminaire de géométrie algébrique, on topos theory and étale cohomology, jointly with Alexander Grothendieck. He also collaborated with Barry Mazur to define étale homotopy theory which has become an important tool in algebraic geometry, and applied ideas from algebraic geometry (such as the Nash approximation) to the study of diffeomorphisms of compact manifolds.

His work on the problem of characterising the representable functors in the category of schemes has led to the Artin approximation theorem in local algebra as well as the "Existence theorem". This work also gave rise to the ideas of an algebraic space and algebraic stack, and has proved very influential in moduli theory.

He also has made important contributions to the deformation theory of algebraic varieties, serving as the basis for all future work in this area of algebraic geometry. With Peter Swinnerton-Dyer, he provided a resolution of the Shafarevich-Tate conjecture for elliptic K3 surfaces and the pencil of elliptic curves over finite fields.

In 2002, Artin won the American Mathematical Society's annual Steele Prize for Lifetime Achievement.

In 2005, he was awarded the Harvard Centennial Medal.

In 2013, he won the Wolf Prize in Mathematics, and in 2015 was awarded the National Medal of Science from the President Barack Obama. *Wik



1943 Klaus von Klitzing (born 28 June 1943, Schroda) is a German physicist, known for discovery of the integer quantum Hall effect, for which he was awarded the 1985 Nobel Prize in Physics.

German physicist who was awarded the Nobel Prize for Physics in 1985 for his discovery, made in 1980, of the quantized Hall effect. Under appropriate conditions the resistance offered by an electrical conductor is quantized; that is, it varies by discrete steps rather than smoothly and continuously. His experiments enabled other scientists to study the conducting properties of electronic components with extraordinary precision. His work also aided in determining the precise value of the fine-structure constant and in establishing convenient standards for the measurement of electrical resistance.*TiS




1948 Kenneth Alan "Ken" Ribet (June 28, 1948 -) is an American mathematician, currently a professor of mathematics at the University of California, Berkeley. His mathematical interests include algebraic number theory and algebraic geometry.
He earned his bachelor's degree and master's degree from Brown University in 1969, and his Ph.D. from Harvard University in 1973.
Ribet is credited with paving the way towards Andrew Wiles's proof of Fermat's last theorem. Ribet proved that the epsilon conjecture formulated by Jean-Pierre Serre was indeed true, and thereby proved that Fermat's Last Theorem would follow from the Taniyama–Shimura conjecture. Crucially it also followed that the full conjecture was not needed, but a special case, that of semistable elliptic curves, sufficed. An earlier theorem of Ribet's, the Herbrand–Ribet theorem, the converse to Herbrand's theorem on the divisibility properties of Bernoulli numbers, is also related to Fermat's Last Theorem. *Wik




1972 Ngô Bảo Châu (June 28, 1972 - ) is a Vietnamese and French mathematician at the University of Chicago, best known for proving the fundamental lemma for automorphic forms proposed by Robert Langlands and Diana Shelstad. In 2004, Chau and Laumon were awarded the Clay Research Award for their achievement in solving the fundamental lemma proposed by Robert Langlands for the case of unitary groups. Chau also became the youngest professor in Vietnam in 2005. His proof of the general case was selected by Time as one of the Top Ten Scientific Discoveries of 2009. In 2010, he received the Fields Medal and in 2012, the Legion of Honour He is the first Vietnamese to receive the Fields Medal *Wik





DEATHS


1527  Abraham Ortelius, (?4 or 14 Apr 1527,  28 June 1598) a Flemish cartographer. In 1570, Ortelius published Theatrum Orbis Terrarum, or Theater of the World. This was the first modern world atlas. It contained 53 maps, and its novelty lay in the fact that the maps were uniform in style, size, and lettering; had been engraved especially for this work; had descriptive text on the back of each map; and covered the entire world, region by region. Most of the maps were not original with Ortelius—he borrowed freely from previous cartographers and he fully credited all his sources—but many of the maps, such as the world map, are brand new.
The Theatrum was an immediate publishing success, and it went through 23 editions and translations in Ortelius’ own lifetime (he died in 1598).  *Linda Hall Library
*Ortelius by Peter Paul Rubens



  




1768 George Hadley (12 Feb 1685; 28 Jun 1768 at age 83) English physicist and meteorologist who first formulated an accurate theory describing the trade winds and the associated meridional circulation pattern now known as the Hadley cell.*TIS Hadley died at Flitton and was buried in the chancel of Flitton church.




1889 Maria Mitchell (August 1, 1818 – June 28, 1889) First American professional woman astronomer, born Nantucket, Mass. While pursuing an amateur interest, on 1 Oct 1847, she gained fame from the observation of a comet which she was first to report.  She died at age 70 in Lynn, Mass.

In 1847, she discovered a comet named 1847 VI (modern designation C/1847 T1) that was later known as "Miss Mitchell's Comet" in her honor. She won a gold medal prize for her discovery, which was presented to her by King Christian VIII of Denmark in 1848. Mitchell was the first internationally known woman to work as both a professional astronomer and a professor of astronomy after accepting a position at Vassar College in 1865.[ She was also the first woman elected Fellow of the American Academy of Arts and Sciences and the American Association for the Advancement of Science


Maria Mitchell, painting by Herminia
 Borchard Dassel, 1852, *Wik

1930 William J Greenstreet graduated from Cambridge and became headmaster of Marling School Stroud. He is best-known as the long-running editor of the Mathematical Gazette.




1956 Friedrich Riesz (Jan. 22, 1880, in Győr; Feb. 28, 1956, in Budapest)
One of the most significant personalities among Hungarian mathematicians.
At the beginning he studied engineering at the Technical University of Zurich, but he soon realized that he was much more interested in mathematics than in technical subjects. So he continued to study at the Royal Hungarian University of Sciences in Budapest. For him the lectures of Gyula Kőnig and József Kürschák meant the most. Then he studied for a year in Göttingen and attended the lectures of David Hilbert and Hermann Minkowski. He obtained his PhD degree and diploma of secondary school teacher of mathematics and physics in Budapest.




1952 William Watson (15 June 1884, Musselburgh, East Lothian, Scotland
- 28 June 1952 , Edinburgh, Scotland) graduated in Mathematics and Physics from Edinburgh University. He became head of the Physics department at Heriot Watt College in Edinburgh.*SAU


1972 Prasanta Chandra Mahalanobis FRS (29 June 1893 – 28 June 1972) was an Indian scientist and applied statistician. He is best remembered for the Mahalanobis distance, (a statistical measure of the distance between a point P and a distribution D, - a multi-dimensional generalization of the idea of measuring how many standard deviations away P is from the mean of D. ) and for being one of the members of the first Planning commission of free india. He made pioneering studies in anthropometry in India. He founded the Indian Statistical Institute, and contributed to the design of large-scale sample surveys *Wik




1893 Eduard Cech, (June 29, 1893 – March 15, 1960) Czech topologist born in Stračov, Bohemia (then Austria-Hungary, now Czech Republic). His research interests included projective differential geometry and topology. In 1921–1922 he collaborated with Guido Fubini in Turin. 

He received his doctoral degree in 1920 at Charles University; his thesis, titled On Curves and Plane Elements of the Third Order, was written under the direction of Karel Petr. He died in Prague.*Wik




1984 Claude Chevalley (11 February 1909, Johannesburg – 28 June 1984, Paris) was a French mathematician who made important contributions to number theory, algebraic geometry, class field theory, finite group theory and the theory of algebraic groups. He was a founding member of the Bourbaki group.

In his PhD thesis, Chevalley made an important contribution to the technical development of class field theory, removing a use of L-functions and replacing it by an algebraic method. At that time use of group cohomology was implicit, cloaked by the language of central simple algebras. In the introduction to André Weil's Basic Number Theory, Weil attributed the book's adoption of that path to an unpublished manuscript by Chevalley.

Around 1950, Chevalley wrote a three-volume treatment of Lie groups. A few years later, he published the work for which he is best remembered, his investigation into what are now called Chevalley groups. Chevalley groups make up 9 of the 18 families of finite simple groups. *Wik

Y. Akizuki, C. Chevalley and A. Kobori




1974  Vannever Bush (March 11, 1890 – June 28, 1974) American electrical engineer and administrator who and oversaw government mobilization of scientific research during World War II. At the age of 35, in 1925, he developed the differential analyzer, the world's first analog computer. It was capable of solving differential equations. He put into concrete form that which began 50 years earlier with the incomplete efforts of Babbage, and the theoretical details developed by Kelvin. This machine filled a 20 x 30 foot room. He innovated one of the largest growing media in our time, namely hypermedia as fulfilled in the Internet with hypertext links *TIS




1989 Charles Wilderman Trigg,(Feb 7, 1898 Baltimore, Md; June 28, 1989 San Diego, Ca.) American engineer, mathematician and educator. Educated in engineering, mathematics and education at University of Pittsburgh, University of Southern California and University of California at Los Angeles. Worked as an industrial chemist and engineer, 1917-1943, and as an educator and administrator, 1946-1963. Served in the United States Navy during World War II. Book review editor of the Journal of Recreational Mathematics. Considered one of the foremost recreational mathematicians of the twentieth century. *U of Calgary Archives




2015 Louis Norberg Howard, (12 March, 1929; Chicago, Il - June 28,2015) emeritus professor of mathematics at MIT, and McKenzie emeritus professor at Florida State University, died on Sunday, at the age of 86.
Howard joined the MIT mathematics faculty in 1955 as an assistant professor, and was promoted to full professor in 1964. He retired from MIT in 1984.
Howard was an applied mathematician who worked primarily in the field of fluid dynamics. He made fundamental contributions to a broad range of subjects, including hydrodynamic stability and geophysical flows. He made a number of key advances in our understanding of turbulent convection, flows in Hele-Shaw cells, salt-finger zones, rotating flows, and reaction-diffusion equations. The power of his mathematical modeling was evident when he transformed qualitative ideas about the bounds on turbulent transport into rigorous mathematical arguments that initiated the field of upper-bound theory.
He received his BA in physics from Swarthmore College in 1950, and his MA and PhD in mathematical physics from Princeton, in 1952 and 1953, respectively, under the supervision of Donald Spencer. He took an appointment as a Higgins lecturer in mathematics at Princeton in 1953, after which he became a research associate in mathematics and aeronautics at Caltech in 1955.
Howard was named a fellow of the American Academy of Arts and Sciences in 1965 and the American Physical Society in 1984, and was elected to the National Academy of Sciences in 1977. In 1997, he was honored with the prestigious Fluid Dynamics Prize of the American Physical Society. *MIT News







Credits :
*CHM=Computer History Museum
*FFF=Kane, Famous First Facts
*NSEC= NASA Solar Eclipse Calendar
*RMAT= The Renaissance Mathematicus, Thony Christie
*SAU=St Andrews Univ. Math History
*TIA = Today in Astronomy
*TIS= Today in Science History
*VFR = V Frederick Rickey, USMA
*Wik = Wikipedia
*WM = Women of Mathematics, Grinstein & Campbell

Pick's Theorem, some history.

  


*Wik


 
Georg Pick was a Jewish Austrian mathematician (murdered during The Holocaust).  In 1880 he received his PhD from University of Vienna under Leo Konigsberger. In 1899 he published a formula for finding the area of a polygon if all the vertices are on lattice points (points whose x and y coordinates on the plane are both integers, although if they are only rational, you can adapt the theorem.)  He presented the formula he created in 1899, in Geometries zur Zahlenlehre in Prague.  He worked at University of Prague and was on the appointments committee and pushed hard for Einstein to get a position in physics there. He was also instrumental in introducing Einstein to Ricci-Curbastro and Levi-Civita which helped him work out the mathematics in the general theory of relativity.  

Hugo Steinhaus caused a surge in the popularity (and knowledge) of the theorem when he used it in his popular, Mathematical Snapshots, in 1969.  (see Google n-gram below)It probably would have been much more popular in 1899 if graph paper had been more in mathematics education, but thirty to fifty years would pass before the paper became popular in geometry and algebra classes. I also think the appearance of the Geoboard created by Egyptian Educator Caleb Gattegno in the fifties was important in applications of Pick's theorem in elementary and middle schools.  I don't know if these still are used much, or any, so I popped an image of one below. My first geoboard was a crude piece of wood with a 6x6 array nails driven by a terrible carpenter, then and now, the writer. 

Pick would never be aware of this late surge of popularity, he died after two weeks in the Theresiestadt prison camp in 1942.  










*Art of Problem Solving

The formula gives the area in two variables, N and B .  N is the number of lattice points inside the polygon (many teachers, and some books, use I, for inside), and B is the number on the boundary.  The area is given by Area = N + B/2 - 1.  The example at the right shows N=3 for the inside points, B= 13 for the boundary points, so our Area = 3 + 13/2 - 1, or 8 1/2 square units.  You can, of course verify this to yourself by counting connecting lines inside and dividing into squares, rectangles, and triangles that are easy to compute.

There is not a higher dimensional analogy of this theorem, counting points inside and on the boundary, but the Ehrhart Polynomial, created by French high school teacher Eugene Ehrhart in the 60's, describes an expression for the volume in terms of the number of interior points in the polytope and dilations.  

You can find more about the theorem and links to some of its extensions at Drexel University where I also found that the original theorem was published in "Geometrisches zur Zahlenlehre" Sitzungber. Lotos, Naturwissen Zeitschrift Prague, Volume 19 (1899) pages 311-319.  


Here are some more sources for information on the method:  


W. W. Funkenbusch
“From Euler’s Formula to Pick’s Formula using an Edge Theorem”
The American Mathematical Monthly
Volume 81 (1974) pages 647-648

In this short paper Funkenbusch shows that Pick's theorem is derived from Euler's Gem using the theorem that Edges = 3I +2B -3, with I and B for inside lattice points and B for boundary points.

Dale E. Varberg
“Pick’s Theorem Revisited”
The American Mathematical Monthly
Volume 92 (1985) pages 584-587

Varberg extends the theorem to cases with polygons with holes in them.  An interesting read.


Branko Grünbaum and G. C. Shephard
“Pick’s Theorem”
The American Mathematical Monthly
Volume 100 (1993) pages 150-161

For young students, the best part of this is the introduction in which the authors describe an applied mathematical approach to timber management, which unknown to the speaker, was Pick's Theorem.

My favorite article to date is by an Eighth grade student, Chris Polis, from Papua, New Guinea in 1991.  He found generalizations of Pick's Thm to several different lattices, Triangular, hexagonal, and a tesselation of the plain by isosceles trapezoids.  He found individual formulas for these, then found a general one for all of them including Pick's Thm, \( A = \frac{e + 2 (i - 1)}{P-2}\) where P is the number of edges in the lattice, e is boundary points and i is interior points.  For a square this would give P=4 and the formula becomes \( A = \frac{e + 2 (i - 1)}{4-2}\) which simplifies to Pick's Thm.  (Wonder what he is doing today?)

You can use this Desmos lattice I plucked from google to try the triangular formula with the 9 boundary points on the edge and 3 in the interior, and confirm that the interior has 13 unit equilateral triangles in area.  



I recently saw another use of the theorem on twitter to answer the following question.  Several people found the right answer with trig, but one saw a different easy solution.  





Draw the lattice and use Pick's Theorem.  



Recently I came across an extension of Pick's theorem that would cover shapes with holes and such that make the original theorem not work (although in many cases a little common sense will still solve them.)  

.The new approach was in the article "Counting Parallel Segments: New Variants of Pick’s Area Theorem" by Alexander Belyaev & Pierre-Alain Fayolle.  I found it in the Mathematical Intelligencer ,Volume 41, pages 1–7, (2019).  


The method counts parallel line segments and parts of segments to find the area of such non-traditional figures.  


The line segments in dark blue are called interior segments,  They contribute one unit each to the area.  In the figure (a) there are eight of them.  The red line segments are called exterior segments, and they add 1/2 a unit.  The light blue segments are partial segments and also count 1/2 unit each. [Notice in the one passing through an interior point (blue) there are two partial segments, one above and one below. ]  So the area would be 8 + 2/2 +4/2 = 11. sq units
Try the (b) image for yourself.  I'll put the answer below after a brief side note; do take time to try one diagram that does work with the regular Pick method, such as the one near the beginning of this article.  It should work for them also.


How many red(edge) lines did you use?  How many drk blue(interior) segments ?  How many partials?
I had two reds on the left edge, two drk blue and one partial on the next vertical row, four drk blue on the third vertical row, and one drk blue on the fourth edge.  That should add up to the same 8 1/2 units as we got the "Pick" way.


OK  so did you get 3 + 2/2 + 4/2 for a total of six square units for the figure (b)?

I think this is an interesting method, and the parallels Don't have to be vertical, horizontal or diagonal at any slope.  try those and see if you get the same area each time.
Good luck!


Saturday, 27 June 2026

Heronian Triangles, A Wonderful Number Theory Topic for Middle School, High School, and Beyond


For this post, I will consider the definition of "Heronian Triangle" to be a triangle with integer sides and integer area. The common alternative of rational units for sides and area seems to be too broad for my taste for use in a middle school setting, although you may extend the definitions as you wish for your class, after all, it is your class.If you introduce the Heronian formula for the area of a triangle, this is a wonderful way to provide practice in using the formula.  \( A^2 = {s(s-a)(s-b)(s-c)}\) where \(s= \frac{a+b+c}{2} \)  And if you need more reason to instruct your students on this topic, consider that, among others, Euler and Gauss both worked on this topic. 

I imagine the easiest introduction is to simply ask, "Is it possible for a triangle to have all integer sides and integer area?"
Students familiar with Pythagorean triples will almost surely discover that some of the ones they know best, actually meet the definition, for example the student favorite 3-4-5 triangle has area of 6. You might mention how incredible that the numbers are in sequence. If a student comes up with the 5-12-13 right triangle, Point out that the area and perimeter are the same integer, 30. Are there any other Heronian triangles that have the same number for area and perimeter? Such triangles are usually called equable. If they don't get this one you can mention it later. In fact there are only five, challenge them to collect the whole set.

After they discover that they can produce an infinite number of Heronian Triangles from right Pythagorean triangles, we might ask if those are the only ones? Are there any non-Right triangles that are Heronian. Some questions you may want them to have time to think about over night. If someone is doing trial and error, they may come across the 5-5-6 triangle which has an area of 12, which means the altitude from the side of six is 4, and in fact,

it can be made of two 3-4-5 triangles. Could you make other non-right triangles by putting together two Pythagorean right triangles? For the teacher, it is good to point out that around 600 AD, BrahamaGupta, the great Indian mathematician and astronomer, pointed out that if you pick any three rational numbers, a, b, and c, then x= \( \frac{1}{2} (\frac{a^2}{b}+b) \) ; y= \( \frac{1}{2} (\frac{a^2}{c}+c) \) and z= \( \frac{1}{2} (\frac{a^2}{b}-b) \) + \( \frac{1}{2} (\frac{a^2}{c}-c) \) will form a scalene triangle which is rational in it's sides and height, and thus it's area. If appropriate values of a, b, and c are selected, these can form integer sides and area. BrahmaGupta also pointed out that in each case, the triangle is formed from two right triangles with a common side length for the altitude. 
Students, or teachers, who liked "The Hitchhiker's Guide to the Galaxy" may enjoy the 7-15-20 triangle which has both perimeter and area of 42. Author Douglas Adams set 42 as the answer to "life, the universe, and everything" and Tony Crilly and Colin Fletcher have dubbed this the "hitchhiker triangle."

Almost every case offers a topic for further exploration, the 3-4-5 triangle is special because it has all three sides in consecutive integers; can there be more of these? With one of two clever programmers in class, this is an easy one to produce a short list, but can they discover a function to predict them. In fact there is a somewhat easy generating function. If we have one that is n-1, n, and n+1, then we can find the next n by the simple Lucas Function \( n_{t+1} = 4 n_t - n_{t-1} \) 
If they haven't found  any others, we might challenge them to defend a 1-2-3 triangle as Heronian.  Is the area an integer?
Using 4 of the 3-4-5 triangle as one middle term, and 2 as the previous middle term, then the function will predict 4(4)-2 as the middle term of another sequential Heronian triangle, 13, 14, 15.  In fact this one was discovered by Heron himself, and he pointed out that it had an area of 84.   

On This Day in Math - June 27

  


Every science that has thriven has thriven upon its own symbols: logic, the only science which is admitted to have made no improvements in century after century, is the only one which has grown no symbols.
Augustus de Morgan


The 178th day of the year; 178 = 2 x 89. Note that 2 and 89 are the smallest and the largest Mersenne prime exponents under 100. *Prime Curios

178 is a palindrome in base 6,\( [454]_6 \) and in base 8 \([262]_8\)

Strangely enough, 178 and 196 are related... In fact, 178 has a square with the same digits as 196:
1782 = 31,684
1962 = 38,416
178 also has a cube with the same digits as 196:
1783 = 5,639,752
1963 = 7,529,536
*Zoo of Numbers

178 = 13^2 + 3^2

178 is a palindrome in base 6 (454), base 7 (343), and base 8 (262)

178 is a semi-prime, the product of 2 and 89, which are the smallest, and largest Mersenne prime exponents under 100.

More Math Facts for each year day here.




EVENTS


432 B.C. Meton observed the summer solstice and began his cycle. Meton was one of the first Greek astronomers to make accurate astronomical observations. It is widely believed that, working with Euctemon, he observed the summer solstice, which marked the Athenian New Year, in 432 BC.
The Metonic cycle appears in the oldest known astronomical device, the Antikythera Mechanism (2nd century BC) together with its multiple the Callippus cycle of 76 years.
The foundations of Meton's observatory in Athens are still visible just behind the podium of the Pnyx, the ancient parliament. Meton found the dates of equinoxes and solstices by observing sunrise from his observatory. The bisectrice of the observatory lies in an easterly direction, between the Acropolis and the Lycabetus hill.*Wik




1739 "Heavens!, Maupertuis is a flea. Is he ever in one place?" So wrote Francoise de Graffigny to a friend about the French mathematician/man of letters, Pierre-Louis Moreau de Maupertuis. Graffigny affectionately gave the nickname to describe his "frenetic ubiquity." *Mary Terrall, The Man Who Flattened the Earth.

A French mathematician, philosopher and man of letters. He became the Director of the Académie des Sciences, and the first President of the Prussian Academy of Science, at the invitation of Frederick the Great.

In the 1730s, the shape of the Earth became a flashpoint in the battle among rival systems of mechanics. Maupertuis, based on his exposition of Newton (with the help of his mentor Johan Bernoulli) predicted that the Earth should be oblate, while his rival Jacques Cassini measured it astronomically to be prolate. In 1736 Maupertuis acted as chief of the French Geodesic Mission sent by King Louis XV to Lapland to measure the length of a degree of arc of the meridian. His results, which he published in a book detailing his procedures, essentially settled the controversy in his favour.






In 1847, New York and Boston were linked by telegraph wires. This enabled the New York newspapers to receive foreign news brought by Cunard's steamers to the Boston port about 190 miles away. When the Cambria next arrived in Boston, three New York Newspapers on 18 Jul 1846 carried identical brief first-day telegraphic summaries of the Cambia's news*. This telegraph link opened three years after the first U.S. telegraph line was opened on 24 May 1844 with a message sent by Samuel Morse 80 miles from Washington D.C. and Baltimore, Md.*TIS


1908 The academy of sciences of Gottingen announced a prize of one hundred thousand marks, according to the will of Dr. Paul Wolfskehl, of Darmstadt, for the proof of Fermat’s great theorem. A German industrialist and amateur mathematician, Wolfskehl bequeathed 100,000 marks to the Göttingen Academy of Sciences to be offered as a prize for a complete proof of Fermat's Last Theorem. On 27 June 1908, the Academy published nine rules for awarding the prize. Among other things, these rules required that the proof be published in a peer-reviewed journal; the prize would not be awarded for two years after the publication; and that no prize would be given after 13 September 2007, roughly a century after the competition was begun. Wiles collected the Wolfskehl prize money, then worth $50,000, on 27 June 1997.
Prior to Wiles' proof, thousands of incorrect proofs were submitted to the Wolfskehl committee, amounting to roughly 10 feet (3 meters) of correspondence. In the first year alone (1907–1908), 621 attempted proofs were submitted, although by the 1970s, the rate of submission had decreased to roughly 3–4 attempted proofs per month. According to F. Schlichting, a Wolfskehl reviewer, most of the proofs were based on elementary methods taught in schools, and often submitted by "people with a technical education but a failed career". In the words of mathematical historian Howard Eves, "Fermat's Last Theorem has the peculiar distinction of being the mathematical problem for which the greatest number of incorrect proofs have been published."*Wik




1966 An almost 300 year old conjecture of Leonhard Euler is proven wrong. Euler had conjectured that, in the fashion that \(x^2 + y^2 = z^2 \) it always takes n terms to sum to an n-th power: two squares, three cubes, four fourth powers,etc. In 1966, L. J. Lander and T. R. Parkin found the first counterexample: four fifth powers that sum to a fifth power. They showed that \( 27^5 + 84^5 + 110^5 + 133^5 = 144^5.\) In 1988 Noam Elkies of Harvard University found a counterexample for fourth powers: \(2,682,440^4 + 15,365,639^4 + 187,960^4 = 20,615,673^4. Subsequently, Roger Frye of Thinking Machines Corporation did a computer search to find the smallest example: 95,800^4 + 217,519^4 + 414,560^4 = 422,481^4.*David Darling


1967 The first ATM in England that was put into use was by Barclays Bank in Enfield Town in North London, United Kingdom, on 27 June 1967. This machine was the first in the UK and was used by English comedy actor Reg Varney, at the time so as to ensure maximum publicity for the machines that were to become mainstream in the UK. This instance of the invention has been credited to John Shepherd-Barron of printing firm De La Rue, who was awarded an OBE in the 2005 New Year's Honours List. His design used special cheques that were matched with a personal identification number, as plastic bank cards had not yet been invented. *Wik (The plaque posted at the sight makes the claim to be the first cash machine in the world, but cash dispensing machines had been installed in Tokyo and another shortly after in Upsalla.)


1977 In 1983, Sally Ride became the first American woman in space. She blasted off aboard Challenger, culminating a long journey that started in 1977 when the Ph.D. candidate answered an ad seeking astronauts for NASA missions.

In a lecture she gave at Berkeley, Ride said she saw the ad on Page 3 of the student newspaper.  "The moment I saw that ad, I knew that's what I wanted to do," she said.

By the time Ride decided to apply to become an astronaut, she had already received degrees in physics and English and was on her way to a Ph.D. in physics from Stanford University.

*HT Lunar Heritage




1977 Italy issued a postage stamp honoring Filippo Brunelleschi (1377–1446). [Scott #1266]. *VFR


1980 Creighton Carvello recited 20,013 digits of π from memory in nine hours and one minute. *VFR

He was a British mnemonist, born in Patna, Bihar, India but lived in the UK from 1949 until his death. His Pi record came in 1979, and in 1987 he appeared on the BBC television program Record Breakers, memorising one shuffled deck of cards in 2 minutes 59 seconds. It was this feat of memory which first inspired Dominic O'Brien, who later went on to gain the title of World Memory Champion eight times.





BIRTHS

1767 Alexis Bouvard (27 June 1767 – 7 June 1843) French astronomer and director of the Paris Observatory, who is noted for discovering eight comets and writing Tables astronomiques of Jupiter and Saturn (1808) and of Uranus (1821). Bouvard's tables accurately predicted orbital locations of Jupiter and Saturn, but his tables for Uranus failed, leading him to hypothesize that irregularities were caused by an unknown perturbing body. This spurred observations leading to the discovery of Neptune by Adams and Leverrier.*TIS




1806 Augustus de Morgan (27 June 1806 – 18 March 1871) born in Madura (now Madurai), India, son of a colonel in the Indian Army. He is best known for his work in Formal Logic. “De Morgan’s Laws”, are contained in his first book (1847), although they were known to Peter of Spain in the fourteenth century. *VFR

The rules can be expressed in English as:

"The negation of a conjunction is the disjunction of the negations." and
"The negation of a disjunction is the conjunction of the negations."

*Wik
When he defined and introduced the term "mathematical induction" (1838), he gave the process a rigorous basis and clarity that it had previously lacked. He originated the use of the slash to represent fractions, as in 1/5 or 3/7. In Trigonometry and Double Algebra (1849) he gave a geometric interpretation of complex numbers. *TIS  A nice blog about De Morgan's life and relationships is at The Renaissance Mathematicus.






1850 Jorgen Pedersen Gram.(June 27, 1850 – April 29, 1916) was a Danish actuary and mathematician who was born in Nustrup, Duchy of Schleswig, Denmark and died in Copenhagen, Denmark.

Important papers of his include On series expansions determined by the methods of least squares, and Investigations of the number of primes less than a given number. The mathematical method that bears his name, the Gram–Schmidt process, was first published in the former paper, in 1883.

For number theorists his main fame is the series for the Riemann zeta function (the leading function in Riemann's exact prime-counting function). Instead of using a series of logarithmic integrals, Gram's function uses logarithm powers and the zeta function of positive integers. It has recently been supplanted by a formula of Ramanujan that uses the Bernoulli numbers directly instead of the zeta function.

Gram was the first mathematician to provide a systematic theory of the development of skew frequency curves, showing that the normal symmetric Gaussian error curve was but one special case of a more general class of frequency curves.

Gram's theorem, the Gram–Charlier series, and Gram points are also named after him.

He died on his way to a meeting of the Royal Danish Academy after being struck by a cyclist.

In mathematics, particularly linear algebra and numerical analysis, the Gram–Schmidt process or Gram-Schmidt algorithm is a way of finding a set of two or more vectors that are perpendicular to each other. *Wik






1899 Lois Wilfred Griffiths (June 27, 1899 – November 9, 1981) was an American mathematician and teacher. She served as a researcher, mathematician, and professor for 37 years at Northwestern University before retiring in 1964. She is best known for her work in polygonal numbers. She published multiple papers and wrote a textbook, Introduction to the Theory of Equations, published in 1945.

Griffiths attended public schools in Washington state, then attended the University of Washington. She served as an assistant to the Comptroller of the university during her undergraduate course. In 1921, she graduated with a bachelor's degree. In 1923 she earned a master's degree, also from the University of Washington, after writing Contact Curves of the Rational Cubic. The paper was published in typewritten arrangement by the University. She was elected as a member of the American Mathematical Society in September 1923, following which her master's thesis was published in the Bulletin of the American Mathematical Society.

In October 1925, she enrolled at the University of Chicago to pursue a doctorate in mathematics. She was supervised for the Ph.D course by well-known mathematician Leonard Dickson. Her thesis Certain quaternary quadratic forms and diophantine equations by generalized quaternion algebras earned her a doctorate degree in 1927.

In 1927, after earning her doctorate, she was engaged as an instructor of mathematics at Northwestern University in Evanston, Illinois, where she spent the remainder of her career. In 1930, she was promoted to assistant professor of mathematics, and in 1938 she was named associate professor. She retired from Northwestern University in 1964 and was named professor emeritus.*Wik



1931 Martinus Justinus Godefriedus Veltman (born June 27, 1931 in Waalwijk) is a Dutch theoretical physicist. He shared the 1999 Nobel Prize in physics with his former student Gerardus 't Hooft for their work on particle theory. In 1963/64, during an extended stay at SLAC he designed the computer program Schoonschip for symbolic manipulation of mathematical equations, which is now considered the very first Computer algebra system. He was awarded the Nobel Prize for Physics in 1999 together with 't Hooft, "for elucidating the quantum structure of electroweak interactions in physics". Veltman is now retired and holds a position of Emeritus Professor at the University of Michigan. Asteroid 9492 Veltman is named in his honor. *Wik




1940 Daniel Gray "Dan" Quillen (June 22, 1940 – April 30, 2011) was an American mathematician. From 1984 to 2006, he was the Waynflete Professor of Pure Mathematics at Magdalen College, Oxford. He is renowned for being the "prime architect" of higher algebraic K-theory, for which he was awarded the Cole Prize in 1975 and the Fields Medal in 1978.

Quillen was a Putnam Fellow in 1959.
Quillen retired at the end of 2006. He died from complications of Alzheimer's disease on April 30, 2011, aged 70, in Florida. *Wik




DEATHS


1829 James Smithson (ca. 1765 – 27 June 1829) English scientist who provided funds in his will for the founding of the Smithsonian Institution, Washington, D.C. "for the increase and diffusion of knowledge." He had inherited his fortune chiefly through his mother's family. He was a chemist and minerologist who published 27 scientific papers. The mineral smithsonite (carbonate of zinc) was named for him.*TIS




1776 Sophie Germain (1 Apr 1776; died 27 Jun 1831 at age 55) French mathematician who is known for her work in number theory and contributions to the applied mathematics of acoustics and elasticity. Germain was self-taught from books, and from lecture notes supplied by male friends attending the Ecole Polytechnique which she, as a woman, was not permitted to attend. Using a male pseudonym, M. LeBlanc,{"In describing the honourable mission I charged him with, M. Pernety informed me that he made my name known to you. This leads me to confess that I am not as completely unknown to you as you might believe, but that fearing the ridicule attached to a female scientist, I have previously taken the name of M. LeBlanc in communicating to you those notes that, no doubt, do not deserve the indulgence with which you have responded." Letter to Gauss (1807)} She corresponded with Lagrange who recognized her skill, and subsequently sponsored her work. She accomplished a limited proof of Fermat's last theorem, for any prime under 100 where certain conditions were met. In 1816, she won a prize sponsored by Napoleon for a mathematical explanation of Chladni figures, the vibration of elastic plates. She died at age 55, from breast cancer.*TIS 
She died before she could receive the honorary doctorate Gauss had persuaded the University of Gottingen to give her. *VFR

She worked in several areas of mathematics and science, including number theory. She proved Fermat's Last Theorem for exponents less than 100. In 1816 she won the Prix Bordin for her work on vibrations of elastic plates. Naturally, she was the first woman to win this prize. The competition question had be first set in 1811, and Germain was the only entry. In the reopened competitions of 1813 she was again the only entry, and she received an honorable mention. In the 1815 competition she was deemed worthy of the prize. *WM
Grave of Sophie Germain in Père Lachaise Cemetery






 1872 Heber Doust Curtis (June 27, 1872 – January 9, 1942) was an American astronomer. He participated in 11 expeditions for the study of solar eclipses, and, as an advocate and theorist that additional galaxies existed outside of the Milky Way, was involved in the 1920 Shapley–Curtis Debate concerning the size and galactic structure of the universe.

He studied at the University of Michigan and at the University of Virginia, earning a degree in astronomy from the latter.

From 1902 to 1920 Curtis worked at Lick Observatory, continuing the survey of nebulae initiated by Keeler. He headed up the Lick southern station in Chile from 1905 until 1909, when he returned to take charge of the Crossley telescope. In 1912 he was elected president of the Astronomical Society of the Pacific.

In 1918 he observed Messier 87 and was the first to notice the polar jet which he described as a "curious straight ray ... apparently connected with the nucleus by a thin line of matter."*Wik

Concerning one of those nebulae, which he referred to as N.G.C. 4486, and which we generally call M87, he noted that this roundish nebula had a “curious straight ray” that seemed to come right out of the center of the nebula .  He obviously saw this on a photograph, since it is impossible to detect with the naked eye, but he did not publish the photograph along with his paper, but here is another ray photo taken by the Hubble Space Telescope.  The jet is 1500 parsecs long, which means that even if you were travelling at Warp One, trekkies, it would take you almost 5000 years to navigate its length. Linda Hall Linrary





1880 Carl Borchardt (22 February 1817 – 27 June 1880) was a German mathematician who worked in a variety of areas in analysis. He edited Crelle's Journal for more than 30 years.*SAU



1883 William H. Spottiswoode FRS HFRSE LLD (11 January 1825 – 27 June 1883) was an English mathematician, physicist and partner in the printing and publishing firm Eyre & Spottiswoode. He was president of the Royal Society from 1878 to 1883.

As a mathematician, he occupied himself with many branches of his favorite science, more especially with higher algebra, including the theory of determinants, with the general calculus of symbols, and with the application of analysis to geometry and mechanics.

In 1870 he was elected president of the London Mathematical Society. In 1871 he began to turn his attention to experimental physics, his earlier researches bearing upon the light polarization and his later work upon the electrical discharge in rarefied gases. He wrote a popular treatise on the former subject for the Nature Series in 1874. In 1878 he was elected president of the British Association and in the same year president of the Royal Society, of which he had been a fellow since 1853.

He died in London of typhoid fever on 27 June 1883 and was buried in the south transept of Westminster Abbey. *Wik




1952 Max Dehn died (November 13, 1878 – June 27, 1952). He solved Hilbert’s third problem in 1900 (shortly after receiving his Ph.D. under Hilbert on another topic in the foundations of geometry): a tetrahedron cannot be cut up into finitely many pieces and reassembled into a cube of equal volume. Thus Dehn became the first mathematician to join “the honors class” of mathematicians who had solved one of the twenty-three problems Hilbert posed in Paris in 1900.

Dehn's doctoral students include Ott-Heinrich Keller, Ruth Moufang, and Wilhelm Magnus; he also mentored mathematician Peter Nemenyi and the artists Dorothea Rockburne and Ruth Asawa.*Wik





1975 Sir Geoffrey Ingram Taylor OM (7 March 1886 – 27 June 1975) was a British physicist, mathematician and expert on fluid dynamics and wave theory. His biographer and one-time student, George Batchelor, described him as "one of the most notable scientists of this (the 20th) century". His final research paper was published in 1969, when he was 83. In it he resumed his interest in electrical activity in thunderstorms, as jets of conducting liquid motivated by electrical fields. The cone from which such jets are observed is called the Taylor cone for his namesake. In the same year Taylor was appointed to the Order of Merit. He suffered a stroke in 1972 which effectively put an end to his work; he died in Cambridge in 1975.

His father, Edward Ingram Taylor, was an artist, and his mother, Margaret Boole, came from a family of mathematicians (his aunt was Alicia Boole Stott and his grandfather was George Boole). As a child he was fascinated by science after attending the Royal Institution Christmas Lectures, and performed experiments using paint rollers and sticky-tape.Taylor read mathematics and physics at Trinity College, Cambridge from 1905 to 1908. He won several scholarships and prizes at Cambridge, one of which enabled him to study under J. J. Thomson.   More about Those Amazing Boole Girls

*Wik




2023 Evelyn Boyd Granville (May 1, 1924 - June 27, 2023 ) was the second African-American woman in the U.S. to receive a PhD in mathematics. (The first was Euphemia Haynes who was awarded her PhD from Catholic University in 1943.)
With financial support from her aunt and a small partial scholarship from Phi Delta Kappa, Granville entered Smith College in the fall of 1941. She majored in mathematics and physics, but also took a keen interest in astronomy. She was elected to Phi Beta Kappa and to Sigma Xi and graduated summa cum laude in 1945. Angeles]]. In L.A., Granville accepted the position of Research Specialist with the Space and Information Systems Division of the North American Aviation Company, but returned to IBM the following year. Both positions involved trajectory analysis and orbit computation. In 1967, Granville’s marriage ended in divorce. At the same time, IBM was cutting staff in Los Angeles, so Granville applied for a teaching position at California State University in Los Angeles, California.
She moved to California State University at Los Angeles in 1967 as a full professor of mathematics and married Edward V. Granville in 1970. After retiring from California State in 1984 she joined the faculty of the University of Texas at Tyler as professor and chair of mathematics. There she developed elementary school math enrichment programs. One of three African American women honored by the National Academy of Science in 1999, she has been awarded honorary degrees by Smith College and Lincoln University. 
Granville died at her apartment in Silver Spring, Maryland on June 27, 2023, at the age of 99*Wik

Dr. Scott Williams at Buffalo has a website about Black Women in Mathematics including many biographies.




Credits :
*CHM=Computer History Museum
*FFF=Kane, Famous First Facts
*NSEC= NASA Solar Eclipse Calendar
*RMAT= The Renaissance Mathematicus, Thony Christie
*SAU=St Andrews Univ. Math History
*TIA = Today in Astronomy
*TIS= Today in Science History
*VFR = V Frederick Rickey, USMA
*Wik = Wikipedia
*WM = Women of Mathematics, Grinstein & Campbell