Tuesday, 7 July 2026

On This Day in Math - July 7

 





Probability is a mathematical discipline whose aims are akin to those, 
for example, of geometry of analytical mechanics.
In each field we must carefully distinguish three aspects of the theory:
(a) the formal logical content,
(b) the intuitive background,
(c) the applications.
The character, and the charm, of the whole structure cannot be appreciated without 
considering all three aspects in their proper relation.

William Feller, An Introduction to Probability Theory and its Applications




The 188th day of the year; 188 is the largest known even number that can be expressed as the sum of two (distinct) primes in exactly five ways. *Prime Curios Students might seek smaller numbers that can be so expressed..

Neither 1882  nor 1883 contain a one or an eight. *@Derektionary

There are 188 11 bead necklaces using two colors, if the necklace can not be turned over.

188 is a Happy number: trajectory under iteration of sum of squares of digits map to 1.

188 is a product of 4 times a number (47). Any such number is the difference of two squares, one of which is the square of one more than the number n/4, and one of which is the square of one less. 48^2-46^2 = 188

The immortal Casey Jones, whose real name was John Luther Jones, of country music ballads was a real guy (and born in the town of Cacey in Fulton County, Ky) and on April 30, 1900 he took off from Jackson, Tennessee bound for Canton, Mississippi on the Cannonball, but was killed in a dark foggy night when a stranded train was on his rail in Vaughn, Mississippi. His skilled driving saved his passengers, but his life ended at mile number 188 of his final drive.




See More Math Facts for every year date here



EVENTS

1339 There was an annular-total eclipse, with the total part of the track finding its way between the Orkney and Shetland Islands without touching either. At this location the track of totality was only 1 km wide, with a duration of 1 second! Presuming that you could position a boat to an accuracy of 1 km, totality must have been a ring of Baily's Beads. *NSEC



1637 In 1625 (Christen Sørensen) Longomontanus suggested to the King, Christian IV, that he should build an observatory to replace Tycho’s Stjerneborg, which had been demolished in 1601. The observatory, the Rundetaarn (Round Tower), was conceived as part of the Trinitatis Complex: a university church, a library and the observatory. The foundation stone was laid on 7 July 1637 and the tower was finished in 1642. Longomontanus was appointed the first director of the observatory, after Leiden, 1632, it was only the second national observatory in Europe. The church and Library were finished in 1657. *RMAT, This 17th Century tower and observatory is one of Copenhagen's most iconic buildings, located on one of the busy shopping streets.



1668, Sir Isaac Newton received his M.A. from Trinity College in Cambridge.*TIS


1742 Goldbach's conjecture was sent in a letter to Leonhard Euler on 7 Jul 1742. Stated in modern terms it proposes that: "Every even natural number greater than 2 is equal to the sum of two prime numbers." It has been checked by computer for vast numbers - up to at least 4 x 1014 - but still remains unproved. *TIS





1747 Johann Sebastian Bach dedicated his Musikalisches Opfer (Musical Offering) to Frederick the Great. For a discussion of the mathematical significance of this cerebral music, see Godel, Escher, Bach: An Eternal Golden Braid by Douglas R. Hofstadter. *VFR


1777 Johan Bernoulli, then astronomer Royal, Berlin, is paid a sum of 84 pounds for the Sexcentenary tables.  "To Mr. John Hyacinth Magellan....for the use of Mr. Bournoulli .. as a reward for his care and trouble in constructing a manuscript Book of Tables for facilita."
Two years later they would pay 28.35 pounds to Dr. Charles Hutton for translating the preface of the tables.


1788 Caroline Herschel's nebula discovery,* History of Astronomy ‏@HistAstro

Caroline Herschel was a German-born British astronomer who was a pioneer in the field and is considered the first professional female astronomer. She made important contributions to the work of her brother Sir William Herschel, executing many of the calculations connected with his studies. On her own, she detected by telescope three nebulae in 1783, and in 1786 she became the first woman to discover a comet; over the next 11 years she spotted seven other comets.

Caroline contracted typhus at the age of 10, and the disease stunted her growth; she grew only 4 feet 3 inches (1.3 metres) tall. Her mother opposed her education, and Caroline instead helped in the management of the household. In 1772 her brother William took her to Bath, England, where he had established himself as a teacher of music. There Caroline trained and performed successfully as a singer. In addition, William tutored her in mathematics. The siblings gave their last public musical performance in 1782, when her brother accepted the private office of court astronomer to George III; the previous year William had discovered the planet Uranus.


1823 William Rowan Hamilton passed into Trinity College, Dublin. He was easily first out of the 100 candidates. *VFR


1847 Lassel discovered a satellite of Neptune. *VFR (this date does not concur with other dates on these discoveries) In 1846 Lassell discovered Triton, the largest moon of Neptune, on October 10, just 17 days after the discovery of Neptune itself by German astronomer Johann Gottfried Galle. In 1848 he independently co-discovered (with William Cranch Bond, his son George Phillips Bond )      Hyperion, a moon of Saturn. In 1851 he discovered Ariel and Umbriel, two new moons of Uranus.*Wik

Hyperion



1855, a letter from Michael Faraday in The Times newspaper, London, described the polluted state of the River Thames he had observed on a boat trip: "The whole of the river was an opaque pale brown fluid. In order to test the degree of opacity, I ... dropped [pieces of card] into the water at every pier the boat came to; before they had sunk an inch below the surface they were indistinguishable, though the sun shone brightly at the time." His words, he said, were no exaggeration, they were "the simple truth." He asserted, "If there be sufficient authority to remove a putrescent pond from the neighborhood of a few simple dwellings, surely the river which flows for so many miles through London ought not to be allowed to become a fermenting sewer." *TIS Things must have gotten better over time, I wrote some dozen years ago about the return of the seahorse to the muddy waters of the Thames. 

FARADAY GIVING HIS CARD TO FATHER THAMES;

And we hope the Dirty Fellow will consult the learned Professor

Punch (21 Jul 1855)



1887  On this day in 1887, Michelson and Morley began the interferometer experiment to try to detect ether. Their result supported special relativity.  *SAU

a supposed medium permeating space that was thought to be the carrier of light waves. The experiment was performed between April and July 1887 by American physicists Albert A. Michelson and Edward W. Morley at what is now Case Western Reserve University in Cleveland, Ohio, and published in November of the same year.

The experiment compared the speed of light in perpendicular directions in an attempt to detect the relative motion of matter, including their laboratory, through the luminiferous aether, or "aether wind" as it was sometimes called. The result was negative, in that Michelson and Morley found no significant difference between the speed of light in the direction of movement through the presumed aether, and the speed at right angles.

This result is generally considered to be the first strong evidence against some aether theories, as well as initiating a line of research that eventually led to special relativity, which rules out motion against an aether. Of this experiment, Albert Einstein wrote, "If the Michelson–Morley experiment had not brought us into serious embarrassment, no one would have regarded the relativity theory as a (halfway) redemption."

Michelson and Morley's interferometric setup, mounted on a stone slab that floats in an annular trough of mercury




1959 Planetary occultations of 1st-magnitude stars are extremely rare. The next time will be when Venus occults Regulus on October 1, 2044.  Such events provide information on the planets size, position, and atmosphere.


1960 Press conference announces discovery of laser to the world. "VoilÁ. that Was It! The Laser was Born!" *Hughes Research Lab Web page.


BIRTHS

1638 Francois or Francois Bertrand Barrême Barrême,(7 July 1638, Tarascon, France - 1703, Paris France) is considered one of the founders of accounting . After having engaged in trading in Italy , he moved to Paris where he gave lessons in bookkeeping and became a protégé of Colbert . Expert for the accounts of the Accounting Chamber of Paris and King's ordinary arithmetician, he is the author of books of mathematical conversions. His books were so common that today his name is used for what was once in English called a "ready reckoner", a table of numbers used to facilitate simple calculations, esp one for applying rates of discount, interest, charging, etc, to different sums . *Wik  

The first known book on accounting was, "Summa de Arithmetica, Geometria, Proportioni et Proportionalità" by Luca Pacioli, published: 1494 in Venice, Italy.  Though Pacioli didn’t invent double-entry bookkeeping, his work was the first to systematically describe it in print.





1673 George Graham, an English clock- and instrument-maker, was born July 7, 1673. The 18th century saw the transformation of the instrument-maker from a lower-class, ill-respected artisan to an honorable gentleman-craftsman, worthy of membership in genteel society. George Graham was mostly responsible for this metamorphosis. He made telescopes and clocks for patrons who were so pleased with Graham’s meticulous handiwork that they saw to it that Graham got a share of the limelight. When Pierre Maupertuis visited London prior to making his trip to Lapland in 1736 to determine the shape of the earth, he was so impressed by Graham that he outfitted his expedition almost exclusively with Graham sextants, theodolites, and telescopes, and he gave Graham credit in his narrative. James Bradley used a Graham zenith telescope to discover the aberration of light in 1729, the first evidence that the earth moved around the sun, and he too credited Graham for his success. The fourth image above shows a side view of a Graham watch of about 1735.


Graham was later inducted into the Royal Society of London, and when he died in 1751, he was buried in Westminster Abbey (interestingly, sharing the grave of his predeceased colleague, Thomas Tompion). There is a plaque honoring both Tompion and Graham at the site of their shop in London (fifth image).

One of Graham’s most notable inventions was the “orrery”, a clockwork device that reproduces the motions of the earth, sun, and moon. The first orrery was built by James Rowley to Graham's design in 1713 for Charles Boyle, the 4th Earl of Orrery, whence the instrument's name. Later orreries would show the motion of other planets as well. The original Rowley/Graham orrery is on display in the Science Museum in London  *Linda Hall Org





1746 Giuseppe Piazzi (July 7, 1746 - July 22, 1826) an Italian mathematician and astronomer. He discovered the asteroid Ceres and established an observatory at Palermo, now the Osservatorio Astronomico di Palermo – Giuseppe S. Vaiana. (for more detail see the source article) *Today in Astronomy



1752 Joseph-Marie Jacquard born (7 July 1752 – 7 August 1834). *VFR French silk weaver, (born Lyons), inventor of the Jacquard programmable power loom for brocaded fabric. His loom would mechanically produce any pattern, controlled by perforated control cards (1805). This served as the impetus for the technological revolution of the textile industry and is the basis of the modern automatic loom. The concept of using punched cards was later applied by Hollerith to keeping track of the 1890 US census data. The idea further evolved to computer input punched cards. *TIS






1816 Rudolf Wolf  (7 July 1816 – 6 December 1893) Swiss astronomer and astronomical historian. Wolf's main contribution was the discovery of the 11 year sunspot cycle and he was the codiscoverer of its connection with geomagnetic activity on Earth. In 1849 he devised a system now known as Wolf's sunspot numbers. This system is still in use for studying solar activity by counting sunspots and sunspot groups. In mathematics, Wolf wrote on prime number theory and geometry, then later on probability and statistics - a long paper discussed Buffon's needle experiment. He estimated by Monte Carlo methods.*TIS



1861 Nettie Maria Stevens (July 7, 1861 – May 4, 1912 American geneticist who was born in the year that the Civil War began, and despite difficult times and limited women’s educational opportunities, became one of the first American women to achieve recognition for her contributions to scientific research. As a cell biologist and geneticist, her great contribution to science was as one of the first scientists to find that sex is determined by a single difference between two classes of sperm—the presence or absence of an X chromosome. *TiS




1888 Archibald Goldie (7 July 1888 in Glenisla, Angus, Scotland - 24 Jan 1964 in London, England) studied at the universities of St Andrews and Cambridge. He served in the Meteorological Service of the British Army in World War I and continued to work in various branches of the Meteorological Office.*SAU


1905 Marie-Louise Dubreil-Jacotin (7 July 1905 – 19 October 1972) was a French mathematician, the second woman to obtain a doctorate in pure mathematics in France, the first woman to become a full professor of mathematics in France, the president of the French Mathematical Society, and an expert on fluid mechanics and abstract algebra.*Wik

In 1926 she ranked second in the entrance examination to the École Normale Supérieure (ENS), but was initially deferred to 21st place due to her gender. A successful appeal reinstated her position. *Sau

Rue Marie-Louise-Dubreil-Jacotin, a street in the 13th arrondissement of Paris within Paris Diderot University, is named after her, and the University of Poitiers also has a street with the same name. In semigroup theory, the Dubreil-Jacotin semigroups are also named after her, as is the Dubreil-Jacotin–Long equation, "the standard model for internal gravity waves" in fluid mechanics. *Wik



1906 William Feller (July 7, 1906 – January 14, 1970). He once said that multiplication, especially before breakfast, is seldom commutative. He died in 1970. *VFR
Feller was one of the greatest probabilists of the twentieth century, who is remembered for his championing of probability theory as a branch of mathematical analysis in Sweden and the United States. In the middle of the 20th century, probability theory was popular in France and Russia, while mathematical statistics was more popular in the United Kingdom and the United States, according to the Swedish statistician, Harald Cramér. His two-volume textbook on probability theory and its applications was called "the most successful treatise on probability ever written" by Gian-Carlo Rota. By stimulating his colleagues and students in Sweden and then in the United States, Feller helped establish research groups studying the analytic theory of probability. In his research, Feller contributed to the study of the relationship between Markov chains and differential equations, where his theory of generators of one-parameter semigroups of stochastic processes gave rise to the theory of "Feller operators".*Wik



1906 Gheorghe Mihoc (July 7, 1906 – December 25, 1981) was a Romanian mathematician and statistician.

On April 28, 1934, he earned his Doctorate in Mathematics from the University of Bucharest, in front of a commission consisting of Dimitrie Pompeiu, as chairman, Anton Davidoglu, and Onicescu. The subject of his thesis, written under the direction of Onicescu, was On the general properties of interdependent statistical variables.

From 1937, Mihoc went to the University of Bucharest as assistant to Octav Onicescu, first at mechanics, then at algebra and probabilities calculation (1937–1942). That same year (1937) he also taught general mathematics with the students from the preparation year of Politehnica University of Bucharest. Between 1942 and 1946 he was conference lecturer of general mathematics at the Faculty of Physics and Chemistry of the University of Bucharest. Then, in 1946, he was appointed professor at the Academy of Higher-level Commercial and Industrial Studies, for financial mathematics (1946–1949).

In 1948, after the reform of education in all degrees, he was appointed head of the department of probability calculation and mathematical statistics at the Faculty of Mathematics and Physics at the University of Bucharest, then as professor and head of the department of applied mathematics. From fall 1962 he was again professor and head of the department of probability calculation and mathematical statistics (successor to Onicescu). As a leading specialist in probability and statistics, he was invited to different countries to give lectures in the field. Mihoc supervised 6 Ph.D. students at the University of Bucharest, including Marius Iosifescu and Radu Theodorescu

In April 1964 he was appointed director of the Statistical Centre of the academy. He was an editor of Gazeta Matematică [ro] and member of the board of C.R.C.C.S. In November 1964 Mihoc was awarded the title of Honorary Professor. In 1971 he was awarded the Order of the Star of the Romanian Socialist Republic, Second class.

A private high school in Bucharest, Sector 1 (founded in 1997) is named after both Onicescu and Mihoc *Wik




1922 Volodymyr Oleksandrovych Marchenko (7 July 1922 - ) is a Soviet and Ukrainian mathematician who specialises in mathematical physics.

 He defended his PhD thesis in 1948 under the supervision of Naum Landkof, and in 1951, he defended his DSc thesis. He worked in Kharkiv University until 1961. For 4 decades, he headed the Mathematical Physics Department at the Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine.

Marchenko was awarded the Lenin Prize in 1962, the N. N. Krylov Prize in 1980, the State Prize of Ukraine in Science and Technology in 1989, and the N. N. Bogolyubov prize in 1996. Since 1969 he is a member of the National Academy of Sciences of Ukraine, since 1987 of the Russian Academy of Sciences and since 2001 of the Royal Norwegian Society of Sciences and Letters.

Marchenko turned 100 on 7 July 2022






DEATHS

1900 Eduard Wiltheiss (12 June 1855 Worms, Germany – 7 July 1900 Halle) was a German mathematician who made major contributions to the theory of abelian functions *VFR

The German Mathematical Society (Deutsche Mathematiker-Vereinigung) was founded in 1890 at a meeting of the Society of German Scientists and Physicians which took place in Bremen from 15 to 20 September. Wiltheiss was a founder member of the German Mathematical Society along with his colleague at Halle Hermann Wiener, as were Cantor, Gordan, Hilbert, Klein, Minkowski, Study and Heinrich Weber who all gave lectures at the Bremen meeting.

The research which Wiltheiss carried out was mostly in the area of abelian functions, in particular studying hyperelliptic functions and theta functions. Following his habilitation, he published papers such as Über die complexe Multiplication hyperelliptischer Functionen zweier Argumente (1883), Über die partiellen Differentialgleichungen zwischen den Ableitungen der hyperelliptischen Thetafunctionen nach den Parametern und nach den Argumenten  (1885), Über-Thetafunctionen, die nach einer Transformation in ein Product von Thetafunctionen zerfallen  (1886), and Über eine partielle Differentialgleichung der Thetafunctionen zweier Argumente und über die Reihenentwicklung derselben  (1887). Over the next couple of years from 1888 to 1890 his output of papers was very high, both in quality and quantity (eight paper were published over this period). However his health deteriorated and his final research paper was Die partiellen Differentialgleichungen der Abel'schen Thetafunctionen dreier Argumente  (1891). Wirtinger writes that Wiltheiss produced many valuable single results, around which new theories developed .




1927 Magnus Gustaf Mittag-Leffler died (16 March 1846 – 7 July 1927) . Swedish mathematician who founded the international mathematical journal Acta Mathematica and whose contributions to mathematical research helped advance the Scandinavian school of mathematics. Mittag-Leffler made numerous contributions to mathematical analysis (concerned with limits and including calculus, analytic geometry and probability theory). He worked on the general theory of functions, concerning relationships between independent and dependent variables. His best known work concerned the analytic representation of a one-valued function, this work culminated in the Mittag-Leffler theorem.*TIS


Mittag-Leffler Institute



1930 Sir Arthur Conan Doyle (22 May 1859 – 7 July 1930) Scottish novelist, physician, spiritualist. His fictional detective, Sherlock Holmes, emulates the scientist, diligently searching through data and to make sense of it. "It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts." *TIS


1942 William Henry Young (London, 20 October 1863 - Lausanne, 7 July 1942) discovered Lebesgue integration, independently but 2 years after Lebesgue. He studied Fourier series and orthogonal series in general.*SAU

He was the husband of Grace Chisholm Young, with whom he authored and co-authored 214 papers and 4 books. Two of their children became professional mathematicians (Laurence Chisholm Young, Cecilia Rosalind Tanner). Young's Theorem was named after him.

In 1913 he was the first to be appointed to the newly created chair of Hardinge Professorship of Pure Mathematics in Calcutta University which he held from 1913 to 1917. He also held the part-time Professorship of Philosophy and the History of Mathematics at the University of Liverpool from 1913 to 1919.*Wik




1975 William Hodge (17 June 1903 – 7 July 1975) studied at Edinburgh and Cambridge Universities. After some time at Bristol and in the USA he returned to Cambridge and became Lowndean Professor of Astronomy and Geometry. His main interests were in Algebraic Geometry and Differential Geometry. He became an honorary member of the EMS in 1954. He was knighted in 1959. *SAU His discovery of far-reaching topological relations between algebraic geometry and differential geometry—an area now called Hodge theory and pertaining more generally to Kähler manifolds—has been a major influence on subsequent work in geometry. *Wik



1982 Raymond Louis Wilder (3 November 1896 in Palmer, Massachusetts – 7 July 1982 in Santa Barbara, California) was an American mathematician, who specialized in topology and gradually acquired philosophical and anthropological interests.

In 1926, Wilder joined the faculty of the University of Michigan at Ann Arbor, where he supervised 26 Ph.Ds and became a research professor in 1947. During the 1930s, he helped settle European refugee mathematicians in the United States. Mathematicians who rubbed shoulders with Wilder at Michigan and who later proved prominent included Samuel Eilenberg, the cofounder of category theory, and the topologist Norman Steenrod. After his 1967 retirement from Michigan at the rather advanced age of 71, Wilder became a research associate and occasional lecturer at the University of California at Santa Barbara.

Wilder was vice president of the American Mathematical Society, 1950–1951, president 1955–1956, and the Society's Josiah Willard Gibbs Lecturer in 1969. He was president of the Mathematical Association of America, 1965–1966, which awarded him its Distinguished Service Medal in 1973. He was elected to the American National Academy of Sciences in 1963. Brown University (1958) and the University of Michigan (1980) awarded him honorary doctorates. The mathematics department at the University of California annually bestows one or more graduating seniors with an award in Wilder's name. *Wik

Wilder moved to the University of Texas in 1921 where again he was appointed as an instructor while he worked for his doctorate. It was here that his interests moved towards pure mathematics under the influence of Robert Moore. When he asked permission from Moore to take his topology course, Moore replied, "No, there is no way a person interested in actuarial mathematics could do, let alone be really interested in, topology."

After Wilder persuaded Moore to let him take the course, Moore proceeded to ignore him until he solved one of the hardest problems Moore posed to the class. Wilder gave up his plans to study actuarial mathematics and became Moore's research student. He suggested Wilder write up the solution to the problem for his doctorate which indeed he did, becoming Moore's first Texas doctorate in 1923 with his dissertation Concerning Continuous Curves. *SAU




2014 Lars Gårding (7 March 1919 – 7 July 2014) was a Swedish mathematician. He made notable contributions to the study of partial differential equations and partial differential operators. He was a professor of mathematics at Lund University in Sweden 1952–1984. Together with Marcel Riesz, he was a thesis advisor for Lars Hörmander.

His interest was not limited to mathematics, but also in art, literature and music. He played the violin and the piano. Further, he published a book on bird songs and calls in 1987, a result of his interest in bird watching.

Gårding was elected a member of the Royal Swedish Academy of Sciences in 1953 and of the Finnish Society of Sciences and Letters in 1985.

Gårding died on 7 July 2014, aged 95. *Wik





2014 Klaus Peters,( --, July 7, 2014) mathematician and STEM Publisher for over 50 years, passed away on July 7, 2014. Klaus, who received his doctorate from University of Erlangen in 1962, became well-known in the mathematical community largely through A.K. Peters Ltd, publisher of scientific and technical books, specializing in mathematics and computer science, as well as journals Experimental Mathematics, Internet Mathematics, and the Journal of Graphics Tools. Klaus was a familiar face at mathematics meetings around the world, and recently consulted with the AMS publishing division on a number of different projects, including Really Big Numbers. He was a strong and eloquent advocate for scholarly publishing. *AMS



2017 Marina Evseevna Ratner ( October 30, 1938 – July 7, 2017) was a professor of mathematics at the University of California, Berkeley who worked in ergodic theory. Around 1990, she proved a group of major theorems concerning unipotent flows on homogeneous spaces, known as Ratner's theorems. Ratner was elected to the American Academy of Arts and Sciences in 1992, awarded the Ostrowski Prize in 1993 and elected to the National Academy of Sciences the same year. In 1994, she was awarded the John J. Carty Award from the National Academy of Sciences.

She studied mathematics and physics at Moscow State University. Here, she became interested in probability theory, inspired by A.N. Kolmogorov and his group. After graduation, she spent four years working in Kolmogorov's applied statistics group. Following this, she returned to Moscow State university for graduate studies were under Yakov G. Sinai, also a student of Kolmogorov. She completed her PhD thesis, titled "Geodesic Flows on Unit Tangent Bundles of Compact Surfaces of Negative Curvature", in 1969. In 1971 she emigrated from the Soviet Union to Israel and she taught at the Hebrew University from 1971 until 1975. She began to work with Rufus Bowen at Berkeley and later emigrated to the United States and became a professor of mathematics at Berkeley.

She became only the third woman plenary speaker at International Congress of Mathematicians in 1994.

Marina Ratner died July 7, 2017, at the age of 78. *Wik





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

Repdigit Endings to Squares... and other powers


James Tanton ‏@jamestanton Wrote:

"2^2 ends with 4 and 12^2 ends with 44. Is there a square than ends 444? How about one that ends 4444?"

To which I think the answer is yes,..... and no.
38 squared is 1444
462 squared is 213444
538 squared is 289444 and there are many more... (so I'm pretty firm on the "yes".)


but I don't think you will ever see a square ending in 4444. Here's why:
This is a list of the square numbers that end in 444 from 1 to 100,000,000

00001444
00213444
00289444
00925444
01077444
02137444
02365444
03849444
04153444
06061444
06441444
08773444
09229444
11985444
12517444
15697444
16305444
19909444
20593444
24621444
25381444
29833444
30669444
35545444
36457444
41757444
42745444
48469444
49533444
55681444
56821444
63393444
64609444
71605444
72897444
80317444
81685444
89529444
90973444
99241444

Notice a pattern? Look at that digit in the thousands place...

Those are the squares of these numbers:
0038
0462
0538
0962
1038
1462
1538
1962
2038
2462
2538
2962
3038
3462
3538
3962
4038
4462
4538
4962
5038
5462
5538
5962
6038
6462
6538
6962
7038
7462
7538
7962
8038
8462
8538
8962
9038
9462
9538
9962

and another pattern appears, that may help us with a more formal proof:

I hadn't thought too much about the idea of digit repeats at the end of squares, and maybe you haven't either, so here is a quick question to get you started.
When speaking of square numbers:
What ending digits can repeat 2, 3 or more times? More particularly, is there any ending digit that repeats four (or more) times?


The problem, and some notes from a curious young reader led me to want to take up cubes. and perhaps other powers.  Would there always be a cap on the repdigit endings at three??,   or would higher powers lead to even longer and longer repdigit endings.

I played around with some small cubes and only got double endings of digits for a while, 14^3 = 2744; 42^3 = 74088; 53^3 = 148877 (cute, double doubles); 64^3 = 262144; 71^3 = 357911; 92^3 = 778688; and 99^3 =970299..... so far we have had 44, 88, 77, 44, 11, 88, 93, and 99.

Being persistent I went away and didn;t thinkof it for a few years, but then I took to Google sheets and ran off a few hundred cubes quickly... and behold, at 192^3 I get 7077888.  

But Wait as I scrolled through my "first thousand cubes list, there it was at 753.... 753^3 = 426,957,777.

Much later I found the cube of 3247 ends in 3333,  I don't think there are any five repdigit endings to the cubes, but if you are a clever programmer with the right equipment and find me wrong (or right) send a message and let me know.  I think more like this will continue with fourth, fifth, and higher powers, but I'm not sure if the length or repdigit endings gets longer and longer, although one anonymous reader teased me with, "Oh, there are some really beautiful patterns in the fourth and fifth powers....  


Am I being Hazed???? 

Anyway if you guys find something that you want to share with the rest of us, send me a note and I will pass it on.





Monday, 6 July 2026

On this day in Marh - July 6

    



"An ideal math talk should contain one proof and one joke and they should not be the same."

Ron Graham


The 187th day of the year; 187^(1*8*7)+1+8+7 is prime. There are only two such (non-zero) numbers. Students might search for the other.

The 187th prime is 1117. 11*17 = 187

187² and 187³ don't have 1, 7, or 8.
*Math Year-Round ‏@MathYearRound

With 187 people in a room, there's a 50% chance that 4 share the same birthday *Derek Orr

187 = 94^2 - 93^2

187 in hexdecimal (base 16) is a tiny number, as small as a BB (there is a joke hidden in there somewhere.)

See More Math Facts for every year date here



EVENTS

1656 Huygen, in a letter to Carcavi, gives the solution, without proof, to a dice throwing probability problem posed by Fermat. (If A wins for Throwing a six, and B wins by throwing a seven, and after A throws once, B and A each roll twice in turns. What are the odds of A winning?) *A History of Probability and Statistics and Their Applications Before 1750 By Anders Hald 



1708, de Moivre wrote again to Johann Bernoulli about Machin's series, on this occasion giving two different proofs that it converged to π. In 1706 William Jones had published a work Synopsis palmariorum matheseos or, A New Introduction to the Mathematics, Containing the Principles of Arithmetic and Geometry Demonstrated in a Short and Easie Method ... Designed for ... Beginners. (This is the book in which Jones first uses Pi in the mathematical sense it is now used)  This contains on page 243 the following passage:-
There are various other ways of finding the lengths or areas of particular curve lines, or planes, which may very much facilitate the practice; as for instance, in the circle, the diameter is to the circumference as 1 to (16/5- 4/239) - 1/3(16/53- 4/2393) &c. = 3.14159 &c. = π. This series (among others for the same purpose, and drawn from the same principle) I received from the excellent analyst, and my much esteemed friend Mr John Machin; and by means thereof, van Ceulen's number, or that in Art. 64.38 may be examined with all desirable ease and dispatch.
Jones also reports that this formula allows π be calculated:-
... to above 100 places; as computed by the accurate and ready pen of the truly ingenious Mr John Machin.
No indication is given in Jones's work, however, as to how Machin discovered his series expansion for π so when de Moivre wrote to Johann Bernoulli on 8 July 1706 telling him about Machin's series for π he suggested that Johann Bernoulli might tell Jakob Hermann about Machin's unproved result. He did so and Hermann quickly discovered a proof that Machin's series converges to π. He produced techniques that show other similar series also converge rapidly to π and he wrote on 21 August 1706 to Leibniz giving details.  Two years later, on 6 July 1708, de Moivre wrote again to Johann Bernoulli about Machin's series, on this occasion giving two different proofs that it converged to π.




1785 The Continental Congress of the United States adopted the decimal system of money with the dollar as unit.


1815 Total solar eclipse on the North Pole. (Ok, I admit, I wouldn't have thought that could happen!)


1819 When Marie Madeleine Sopie Blanchard ascended in her hydrogen balloon to watch a firework,  she would become the first woman to lose her life while flying. Her craft crashed on the roof of a house and she fell to her death. *yovisto.

Sophie Blanchard, a French balloonist, died July 6, 1819, at the age of 41. Had we posted a Scientist of the Day on July 4, we might have honored Jean-Pierre Blanchard, born on that day in 1753, who was one of the very first balloonists in the heady days of 1783 and the Montgolfier brothers, and who made the first crossing ever of the English Channel in 1785, in a hydrogen (not a hot-air) balloon. He married Sophie in 1804 and she made many balloon flights with him.

When Jean-Pierre suffered a heart attack in 1808 and fell from his balloon, dying from his injuries in 1809, Sophie decided to carry on alone, making more than 60 ascents over the next ten years. She specialized in night flights, and she attracted the favorable attention of both Napoleon and King Louis XVIII, two enemies that it was not easy for one person to please. It is not surprising, given the hazards of her profession (hydrogen balloons were highly flammable), that Sophie met her end in a balloon, or, more accurately, just out of one. On this day in 1819, she took part in a festival in Paris that involved setting off fireworks from her balloon while aloft, which was not the best of ideas. One of the rockets went astray, punctured the balloon, and set it afire. The flaming balloon slowly lost its lifting capacity and descended over the rooftops of Paris. When the gondola struck a roof, Sophie was pitched out of the nacelle and fell to her death.

Louis Figuier’s Les merveilles de la science (1867), this illustration.

 The  image, depicting Sophie’s demise in color, is from a tea card (ca. 1895) from a collection in the Library of Congress.

Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to ashworthw@umkc.edu.



1863  Most people don't think of Marx as being a mathematician, but in fact his work takes up volumes and influenced the Chinese mathematics.  In his early learning he wrote this note to Engels.  *Dirk J Struik


My 2011 paper when I first started learning that Marx even did math, is here  



1895 Number puzzles appeared in newspapers in the late 19th century, when French puzzle setters began experimenting with removing numbers from magic squares. Le Siècle, a Paris daily, published a partially completed 9×9 magic square with 3×3 subsquares on November 19, 1892. It was not a Sudoku because it contained double-digit numbers and required arithmetic rather than logic to solve, but it shared key characteristics: each row, column and subsquare added up to the same number. On July 6,  Le Siècle's rival, La France, refined the puzzle so that it was almost a modern Sudoku and named it carré magique diabolique ('diabolical magic square'). It simplified the 9×9 magic square puzzle so that each row, column, and broken diagonals contained only the numbers 1–9, but did not mark the subsquares. Although they were unmarked, each 3×3 subsquare did indeed comprise the numbers 1–9, and the additional constraint on the broken diagonals led to only one solution. (below)

The modern Sudoku was most likely designed anonymously by Howard Garns, a 74-year-old retired architect and freelance puzzle constructor from Connersville, Indiana, and first published in 1979 by Dell Magazines as Number Place (the earliest known examples of modern Sudoku).*Wik 




1909 Einstein resigns his position at the Bern Patent Office to move to Zurich to take up his first full-time academic position in the newly established chair of theoretical physics at the University of Zurich. His lectures were extremely popular due to his humor, unusual presentations, patience and accommodation to his students to make sure they understood. *Brody & Brody, The Science Class You Wish You Had


In 1920, a radio compass was used for first time for aircraft navigation. In a test of the radio compass as an aid to navigation, an F5L left Hampton Roads and flew directly to the battleship Ohio (BB 12), 94 miles at sea in a position unknown to the pilot. Without landing, the plane made the return trip to Hampton Roads, this time navigating by signals from Norfolk. *TIS

*Smithsonian



1996  Internet service provider America Online Inc. settles lawsuits filed in California that had accused the company of misleading subscribers about how it computes monthly service charges. As part of the settlement, customers received $22 million in free online time and cash rebates.



2016 Astronomy Magazine announces that China has completed the world's largest radio telescope.

E.T. may be easier to find now that China has just finished installation of the 4,450 triangular panels on the world's largest radio telescope, the Five Hundred Meter Aperture Spherical Telescope (FAST). The telescope was finished nearly three months ahead of schedule, with the original ETA in September. With its enormous size of 30 soccer fields, FAST has taken nearly five years and $180 million to build.
So how big is it? One of the scientists that worked on building FAST told Xinhua that if the dish were to be completely filled with wine, there would be enough to give five bottles to all seven billion people on Earth.
The next largest radio telescope is the 305-meter-wide Arecibo Telescope in Puerto Rico, which was completed in 1963. The Arecibo Telescope has held the crown of largest radio telescope for 53 years. FAST is 64 percent larger.


*Astronomy Magazine



BIRTHS

1849  Alfred Bray Kempe (6 July 1849, Kensington, London – 21 April 1922, London) published a false "proof" of the four color theorem in 1879 which stood until Heawood showed the mistake 11 years later. The 'proof' is however still the basis for the computer aided proof discovered 100 years later.*SAU
Much later, his work led to fundamental concepts such as the Kempe chain and unavoidable sets.

Kempe, it seems was really good at near misses.  In 1876 he published his article On a General Method of describing Plane Curves of the nth degree by Linkwork, which presented a procedure for constructing a linkage that traces an arbitrary algebraic plane curve. This was a remarkable generalization of his work on the design of linkages to trace straight lines. This direct connection between linkages and algebraic curves is now called Kempe's universality theorem. While Kempe's proof was flawed, the first complete proof was provided in 2002, based on his ideas.

The Sylvester–Kempe Inversor draws a straight line.






1883 Ernst Arnold Kohlschütter (July 6, 1883 – May 28, 1969) a German astronomer and astrophysicist from Halle.
In 1908 he was awarded his Ph.D. from the University of Göttingen.
In 1911 he began working at the Mount Wilson Observatory, studying the spectra of the Sun and stars. In collaboration with Walter Sidney Adams, and in 1914 they discovered that the absolute luminosity of a star was proportional to the relative intensity of the lines in the spectrum. This allowed astronomers to determine the distance of stars, including main sequence and giants, using the spectroscope.
He became the director of the Bonn observatory in 1925. Therein he was dedicated to astrometric studies.
The crater Kohlschütter on the Moon is named in his honor. *Today in Astronomy




1910 Lothar Collatz  (July 6, 1910, Arnsberg, Westphalia – September 26, 1990, Varna, Bulgaria) was a German mathematician. In 1937 he posed the famous Collatz conjecture, which remains unsolved.
The Collatz conjecture is also known as the 3n + 1 conjecture, the Ulam conjecture (after Stanisław Ulam), Kakutani's problem (after Shizuo Kakutani), the Thwaites conjecture (after Sir Bryan Thwaites), Hasse's algorithm (after Helmut Hasse), or the Syracuse problem; the sequence of numbers involved is referred to as the hailstone sequence or hailstone numbers, or as wondrous numbers.
Take any natural number n. If n is even, divide it by 2 to get n / 2, if n is odd multiply it by 3 and add 1 to obtain 3n + 1. Repeat the process (which has been called "Half Or Triple Plus One", or HOTPO indefinitely. The conjecture is that no matter what number you start with, you will always eventually reach 1. The property has also been called oneness.

Paul Erdős said about the Collatz conjecture: "Mathematics is not yet ready for such problems." and also offered $500 for its solution.
In 2006, researchers Kurtz and Simon, building on earlier work by J.H. Conway in the 1970s, proved that a natural generalization of the Collatz problem is undecidable. However, as this proof depends upon the generalization, it cannot be applied to the original Collatz problem. *Wik




 1917  Henry Jack FRSE (6 July 1917 – 5 January 1978) was a Scottish mathematician at University College Dundee. The Jack polynomials are named after him. His research dealt with the development of analytic methods to evaluate certain integrals over matrix spaces. His most famous paper relates his integrals to classes of symmetric polynomials important in the theory of the representation of the symmetric group. He discovered a new, natural basis for the symmetric polynomials.
In 1970 he was elected a Fellow of the Royal Society of Edinburgh. His proposers were W Norrie Everitt, D S Jones, John Frank Allen, Robert Alexander Rankin and Anthony Elliot Ritchie. He won the Society's Keith Prize for the period 1967/69.

He died of liver cancer at home at 77 Blackness Avenue in Dundee on 5 January 1978.
 The Jack polynomial is a homogeneous, symmetric polynomial which generalizes the Schur and zonal polynomials, and is in turn generalized by the Heckman–Opdam polynomials and Macdonald polynomials.




 1928  Bernard Malgrange (6 July 1928 – 5 January 2024) was a French mathematician who worked on differential equations and singularity theory. He proved the Ehrenpreis–Malgrange theorem and the Malgrange preparation theorem, essential for the classification theorem of the elementary catastrophes of René Thom. 

He received his Ph.D. from Université Henri Poincaré  in 1955. His advisor was Laurent Schwartz. He was elected to the Académie des sciences in 1988. 

In 2012 he gave the Łojasiewicz Lecture (on "Differential algebraic groups") at the Jagiellonian University in Kraków. Malgrange died on 5 January 2024, at the age of 95.





1945 Leon Melvyn Simon FAA, (July 6, 1945 -  ), is a Leroy P. Steele Prize and Bôcher Prize-winning mathematician, known for deep contributions to the fields of geometric analysis, geometric measure theory, and partial differential equations. He is currently Professor Emeritus in the Mathematics Department at Stanford University.

Simon's best known work, for which he was honored with the Leroy P. Steele Prize for Seminal Contribution to Research, deals with the uniqueness of asymptotics of certain nonlinear evolution equations and Euler-Lagrange equations. The main tool is an infinite-dimensional extension and corollary of the Łojasiewicz inequality, using the standard Fredholm theory of elliptic operators and Lyapunov-Schmidt reduction. The resulting Łojasiewicz−Simon inequalities are of interest in and of themselves and have found many applications in geometric analysis.

Simon has more than 100 'mathematical descendants', according to the Mathematics Genealogy Project. Among his doctoral students there is Richard Schoen, a former winner of the Bôcher Memorial Prize.





DEATHS


1476 Regiomontanus, aka Johann Mueller, (6 Jun 1436, 6 Jul 1476 at age 40)the father of trigonometry as a science independent of astronomy. According to a rumor repeated by Gassendi in his Regiomontanus biography he was assassinated by relatives of George of Trebizond whom he had criticized in his writings. More likely he died in an epidemic raging in Rome at the time.The ideas behind the law of sines, like those of the law of cosines, predate the word sine by over a thousand years. Theorems in Euclid on lengths of chords are essentially the same ideas we now call the law of sines. The law of sines for plane triangles was known to Ptolemy and by the tenth century Abu'l Wefa had clearly expounded the spherical law of sines. It seems that the term "law of sines" was applied sometime near 1850, but I am unsure of the origin of the phrase.
The spherical law of sines was first presented by Johann Muller in his De Triangulis Omnimodis in 1464. This was the first book devoted wholly to trigonometry (a word not then invented). David E. Smith suggests that the theorem was Muller's invention.
The German astronomer and mathematician who was chiefly responsible for the revival and advancement of trigonometry in Europe. His book De triangulis omnimodis (1464) is a systematic account of methods for solving triangles. Much of the material on spherical trigonometry in Regiomontanus' On Triangles was taken directly and without credit from the twelfth-century work of Jabir ibn Aflah otherwise known as Geber, as noted in the sixteenth century by Gerolamo Cardano.
In Jan 1472 Muller made observations of a comet which were accurate enough to allow it to be identified with Halley's comet 210 years later (being three returns of the 70 year period comet). He also observed several eclipses of the Moon. His interest in the motion of the Moon led him to make the important observation that the method of lunar distances could be used to determine longitude at sea. However, instruments of the time lacked the necessary accuracy to use the method at sea. *TIS
Thony C who writes the excellent history blog, The Renaissance Mathematicus, noted, "However at least in the case of Regiomontanus appearances are deceptive; what we have here is a date of death that is anything but certain.".  See his explanation of the remark here.
  Although the work was written in 1464, it was not published until 1533.




1854  Georg Simon Ohm (17 March 1789 – 6 July 1854) was a German physicist. As a high school teacher, Ohm began his research with the recently invented electrochemical cell, invented by Italian Count Alessandro Volta. Using equipment of his own creation, Ohm determined that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current. This relationship is now known as Ohm's law.*Wik





1915 Lawrence Hargrave(29 Jan 1850, 6 Jul 1915 at age 65) Australian aeronaut and inventor best known for his invention of the box kite. Hargrave “flew” on 12 Nov 1894, by attaching himself to a huge four kite construction attached to the ground by piano wire. Due to their abilities to carry heavy payloads, steady flight, and capacity for high altitude flight, these kites have had many industrial and military uses in the past. Box kites were used until the 1930's to carry meteorological equipment for high altitude weather studies and by the Royal Air Force as sea rescue equipment to deliver radio aerials. Hargrave also made important studies of wing surfaces and worked with rotary engines and gliders. *TIS

*Scouting Life



 1959 Agnes Ermina Wells, Ph.D. (January 4, 1876, Saginaw, Michigan – July 6, 1959, Saginaw, Michigan) was an American educator and a women's equal rights movement activist. She was Dean of Women at Indiana University and professor of mathematics and astronomy there.

She attended the Arthur Hill High School and she then spent one year at the Saginaw County Training School for Teachers. Wells spent another year in Dresden, Germany, where she studied the German language and music. She studied at Bryn Mawr College before transferring to the University of Michigan, where she studied mathematics and graduated in 1903 with a Bachelor of Arts. In 1916, she earned her Master of Arts degree from Carleton College in Minnesota, where her field of study was astronomy. After completing her dissertation under the Detroit Observatory’s Director Ralph Hamilton Curtiss on A Study of the Relative Proper Motions and Radial Velocities of Stars in the Pleiades Group, she received her Ph.D. in astronomy from the University of Michigan in 1924.

In 1917, she was a faculty member and during the summers she was dean of women at the University of Michigan in Ann Arbor.  At the Helen Newberry Residence, she was the social director. She then went to Indiana University and taught mathematics and was the dean of women beginning in 1919. Wells provided guidance to female students and  assisted with them housing, as well as being credited with establishing the dormitory system at the school. In 1924, she became a member of the Indiana Academy of Science, and that year also began to teach astronomy courses. She retired as the dean of women in 1938, and she taught mathematics and astronomy at the university from that point until 1944. The Agnes E. Wells quadrangle at Indiana University comprises four buildings: Morrison Hall, Sycamore Hall, Memorial Hall, and Goodbody Hall, all built between 1925 and 1940.

For the American Association of University Women, she established a fellowship fund in the amount of $1 million.

The Agnes E Wells Quadrangle, Indiana University




2013 Ismail Jacobus Mohamed (27 July 1930 – 6 July 2013) was a South African activist and mathematician. He represented the African National Congress (ANC) in the National Assembly from 1994 to 2009.

Long associated with the University of the Witwatersrand, Mohamed was best known academically for his work in group theory, including his work on Heineken-Mohamed groups with Hermann Heineken. At the same time, he was a labour and anti-apartheid activist from the 1950s onwards, and he was a leading figure in the Non-European Unity Movement, the Transvaal Indian Congress, and the United Democratic Front in the former Transvaal. Between stints in universities abroad, he was a defendant in the Pietermaritzburg Treason Trial of 1985. Both for his political activism and his academic achievement, he was admitted posthumously to the Order of Mapungubwe in 2014.



2020 Ronald Lewis Graham (born October 31, 1935- Jul 6 2020) is a mathematician credited by the American Mathematical Society as being "one of the principal architects of the rapid development worldwide of discrete mathematics in recent years". He has done important work in scheduling theory, computational geometry, Ramsey theory, and quasi-randomness. Graham was also featured in Ripley's Believe It or Not for being not only "one of the world's foremost mathematicians", but also "a highly skilled trampolinist and juggler", and past president of the International Jugglers' Association. He is currently the Chief Scientist at the California Institute for Telecommunications and Information Technology (also known as Cal-(IT)2) and the Irwin and Joan Jacobs Professor in Computer Science and Engineering at the University of California, San Diego. *Wik My current favorite Graham quote is, "An ideal math talk should contain one proof and one joke and they should not be the same."

His main research partner over the years was his wife, Fan Chung Graham, with whom he authored more than 100 papers. She is on faculty in the UC San Diego Department of Mathematics as an emerita. 

“In our married life, most of the time we are doing mathematics together. It’s like our toy. And it’s particularly fun to do it with Ron. It’s why we have so many joint papers,”

.His long friendship with influential mathematician Paul Erdős, with whom he co-authored nearly 30 papers, also resulted in Graham’s 1979 paper that introduced the concept of an “Erdős number,” showing how closely other mathematicians were tied to Erdős based on the number of publications they co-authored with Erdős. Ron Graham’s Erdős number: 1 (reserved for Erdos’s immediate coauthors.) This concept later took hold in Hollywood as the basis of the popular “Six Degrees of Separation” game calculating how close an actor got to appearing in a movie with Kevin Bacon. 

Graham died of bronchiectasis on July 6, 2020, at the age of 84.

*New York Times




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