Thursday, 3 October 2013

On This Day in Math - October 3


Nature to him (Newton) was an open book, whose letters he could read without effort.
~Albert Einstein

The 276th day of the year; 276 is the sum of twelve consecutive prime numbers (5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43). And from the trivia file, 276 is the number of rounds of the longest boxing match in history. Jack Jones beat Pat Tunney in a bare-knuckle fight in 1825 after 4 1/2 hours.

EVENTS

1533 The mathematical mystic Michael Stifel predicted that on this date a chariot would touch down on a nearby hilltop and conduct him and his followers to heaven. His followers quit their jobs, but as the day approached they became sceptical. Stifel convinced the local constabulary to lock him in jail on the appointed date where he would be safe from his ruined, irate parishioners. *Journal of Recreational Mathematics 6 (1973), pp. 221–223,

1842 Arthur Cayley admitted to fellowship at Trinity College Cambridge, at age 21—younger than any other fellow at the College.*VFR

1846 Sir John Herschel published John Couch Adams’s prediction that a new planet (now called Neptune) existed and where to look for it. This provoked a priority controversy as the planet had already been found 23 September 1846 based on Leverrier’s calculations. *VFR

1896 Einstein graduates from high school in Switzerland at the age of 17. In contrast to the commonly held belief that he was a poor student, his marks are very good, with top scores (6) in all the math and physics courses and fives in most of the others. His lowest mark was in French, but he also took German and Italian; and years later on a visit to Jeruselum he gave a lecture in fluent French. *Einstein Gallery
Einstein said "I never failed in mathematics... Before I was fifteen I had mastered differential and integral calculus.

1950 Transistor Inventors Receive Patent. The U.S. Patent Office issued a patent to John Bardeen, Walter Brattain, and William Shockley for the transistor. The three AT&T Bell Laboratories researchers had successfully tested the first of their devices two years earlier. The transistor started a revolution in computer engineering that led to the development of the semiconductors, microprocessors, and integrated circuits common in modern computers. *CHM

In 1967, the X-15 rocket plane achieved a world record speed of Mach 6.7, which is 4,520 mph or over a mile per second, with U.S. Air Force pilot Pete Knight. It reached an altitude of 192,100 feet (58,552 m). Its internal structure of titanium was covered with a skin of Inconel X, a chrome-nickel alloy. To save fuel, the X-15 was air launched from a B-52 aircraft at about 45,000 ft. Test flights between 8 Jun 1959 and 24 Oct 1968 provided data on hypersonic air flow, aerodynamic heating, control and stability at hypersonic speeds and piloting techniques for reentry used in the development of the Mercury, Gemini, and Apollo spaceflight programs. The X-15 reached 354,200 feet (67 miles) on 22 Aug 1963. *TIS

2011 Scientists from Nottingham, England, officially broke the Guinness World Record for writing the world’s smallest periodic table — engraving it on a single strand of hair.
The scientists from the University of Nottingham’s Nanotechnology and Nanoscience Center placed the table of elements on the hair of Martyn Poliakoff, a chemistry professor, using a beam of accelerated gallium ions. It’s so small that a million tables of the same size could fit on a typical Post-it note.
The hair was presented to the Professor as a birthday gift.
Guinness confirmed that it was the smallest periodic table in existence. *ABC


BIRTHS

1830 George Bailey Brayton (3 Oct 1830; 17 Dec 1892) was an American engineer who invented the first commercial gas internal combustion engine (patented 2 Apr 1872), which he manufactured and sold in the Providence, Rhode Island, area. Its principle of continuous ignition later became the basis for the turbine engine. A pressurized air-fuel mixture from a reservoir was ignited upon entering a water-cooled cylinder. The Brayton engine was given trials powering watercraft, one of John Holland's submarines and one used for a few months installed in a carriage (1872-3). His earlier career included developing steam engines.*TIS

1863 Stanisław Zaremba (October 3, 1863 – November 23, 1942) was a Polish mathematician. His research in differential equations, applied mathematics, classical analysis, particularly on harmonic analysis, was widely recognized. He was a mathematician who contributed to the success of the Polish School of Mathematics through his teaching and organizational skills as well as through his research. Zaremba wrote a number of university textbooks and monographies.
He was a professor of the Jagiellonian University (since 1900), member of Academy of Learning (since 1903), co-founder and president of the Polish Mathematical Society (1919).*Wik

1944 Pierre René Deligne(3 Oct 1944, ) Belgian mathematician who was awarded the Fields Medal at the International Congress of Mathematicians in Helsinki, Finland, in 1978 for his work in algebraic geometry. His work originated with André Weil's ideas on polynomial equations which led to three questions on what properties of a geometric object can be determined purely algebraically. These three problems quickly became major research challenges to mathematicians. A solution of the three Weil conjectures was given by Deligne. This work brought together algebraic geometry and algebraic number theory. The solution to these problems had required the development of a new kind of algebraic topology. *TIS




DEATHS

1891 François Edouard Anatole Lucas (4 April 1842, 3 Oct 1891)    Lucas is best known (to formal mathematicaticians) for his results in number theory: in particular he studied the Fibonacci sequence and the associated Lucas sequence is named after him. He gave the well-known formula for the Fibonacci numbers
√5 fn = ((1 + √5)/2)n - ((1 - √5)/2)n.
Lucas also devised methods of testing primality, essentially those used today. In 1876 he used his methods to prove that the Mersenne number 2127 - 1 is prime. This remains the largest prime number discovered without the aid of a computer.   (For recreational mathematicians), Lucas is also well known for his invention of the Tower of Hanoi puzzle and other mathematical recreations. The Tower of Hanoi puzzle appeared in 1883 under the name of M. Claus. Notice that Claus is an anagram of Lucas! His four volume work on recreational mathematics Récréations mathématiques (1882-94) has become a classic.*SAU  Lucas is also remembered for his unusual death, caused by a waiter dropping a plate which shattered sending a piece of plate into his neck. Lucas died several days later from a deadly inflamation of the skin and subcutaneous tissue caused by streptococcus. The disease, officially listed as erysipelas (from the Greek for "red skin") was more commonly known as "Saint Anthony's Fire". *Pballew.net

1914 René Eugène Gateaux (5 May 1889 - 3 October 1914), was a French mathematician. He is known for the Gâteaux derivative. Part of his work has been posthumously published by Paul Lévy. Gâteaux was killed during World War I. *Wik

1932 Maximilian Franz Joseph Cornelius Wolf (21 Jun 1863, 3 Oct 1932) was a German astronomer who founded and directed the Königstuhl Observatory. He used wide-field photography to study the Milky Way and used statistical treatment of star counts to prove the existence of clouds of dark matter. He was among the first astronomers to show that the spiral nebulae have absorption spectra typical of stars and thus differ from gaseous nebulae. His most important contribution was the introduction of photography to discover hundreds of asteroids, the first of which he named Brucia in honor of the donor of his 16-inch double telescope, Catherine Wolfe Bruce. *TIS

1951 William Leslie Thomson studied at Edinburgh and Cambridge. He taught at Kirkwall, at Kilmarnock and at George Heriot's School in Edinburgh. He became President of the EMS in 1904. *SAU

2006 John Crank (6 February 1916 – 3 October 2006) was a mathematical physicist, best known for his work on the numerical solution of partial differential equations.
He worked on ballistics during the Second World War, and was then a mathematical physicist at Courtaulds Fundamental Research Laboratory from 1945 to 1957. In 1957, he was appointed as the first Head of Department of Mathematics at Brunel College in Acton. He served two terms of office as Vice-Principal of Brunel before his retirement in 1981, when he was granted the title of Professor Emeritus.
Crank's main work was on the numerical solution of partial differential equations and, in particular, the solution of heat-conduction problems. He is best known for his work with Phyllis Nicolson on the heat equation, which resulted in the Crank–Nicolson method.*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

Wednesday, 2 October 2013

On This Day in Math - October 2


Euler calculated without effort, just as men breathe, as eagles sustain themselves in the air.
~François Arago

The 275th day of the year; 275 is the number of partitions of 28 in which no part occurs only once. (Students might try finding the similar number of partitions for 10, or some smaller number to get a sense for how they grow)


EVENTS
479 B.C.: an Annular Solar Eclipse known as "Xerxes' eclipse" as noted by Herodotus occurred. David Dickinson ‏@Astroguyz

On October 2, 1608, the Dutch Estates General examined an application for a patent for "a device to observe things at a distance" presented by a certain Hans Lipperhey (?-1619) an obscure spectacles-maker from Middelburg, in southwestern Holland The patent application was rejected on the grounds that, although the usefulness of the device was recognised, especially for military purposes it was deemed impossible to keep the secret of its construction for very long. And especially considering that, in those same days, another instrument-maker - a certain Sacharias Janssen (1588-1630), he too a spectacles-maker in Middelburg, indicated by Pierre Borel (c. 1620-1671) a few decades later as the true inventor of the telescope - declared that he knew how to build the instrument.*Institute and Museum of the History of Science
I doubt that many modern science/math historians believe that Lipperhey invented the telesccope, and neither did any of the myriad other names suggested over the years.
The first historical construct concerns the ‘invention’ itself, because what happened in
1608 was in fact not an invention at all, but merely a recognition of the great potential of a device, which must have been around for some decades, as a kind of toy or as a device whose purpose was to correct or improve vision. Indications of the awareness of the magnifying power of a combination of two lenses, long before the year 1608, are indeed abundant in the contemporary literature. For instance, in 1538 the Italian scholar Girolamo Fracastoro wrote: ‘If someone looks through two eye-glasses, of which one is placed above the other, he shall see everything larger and more closely.’
After seeing or hearing of Lipperhey’s telescope, many scholars had a kind of déjà vu -feeling. Girolamo Sirtori, who in 1612, only four years after the emergence of the instrument, composed his well-known Telescopium, captured this feeling in the following phrase: "It appeared that this conception was in the minds of many men, so that once they
heard about it, any ingenious person began trying to make one, without [the help of ]
a model."
*Huib J. Zuidervaart, The ‘true inventor’ of the telescope. A survey of 400 years of debate origins of the telescope

1667 Newton became a fellow at Trinity College, Cambridge. *VFR

1759 “Your solution of the isoperimetric problems leaves nothing to be desired and I rejoice that this subject, with which I have been so completely occupied since my first efforsts, has been carried by you to such a high degree of perfection. The importance of the subject has stimulated me to develop, aided by your lights, an analytical solution that I will keep secret as long as your own meditations are not published, lest I take away from you a part of the glory you deserve.” So wrote Euler to the young Lagrange. See Allen Shields, “Lagrange and the M´ecanique Analytique,” The Mathematical Intelligencer, 10:4, Fall 1988, pp. 7– 10. *VFR

1836 Charles Darwin returned from his voyage on the HMS Beagle to the Pacific. It would be 23 years before he published Origin of Species. *TIS

1856 Sylvester was to dine with Charles Wheatstone, the noted physicist and inventor, and had invited Arthur Cayley to attend and meet Wheatstone. Wheatstone had supported Sylvester's successful candidacy for the Royal Society in 1836. James Joseph Sylvester: Life and Work in Letters, *James Joseph Sylvester: Life and Work in Letters
edited by Karen Hunger Parshall
1912 Ernest Rutherford presents his theory of the structure of the Atom to a session of the Manchester Literary and PHilosophical Society. He rejected Thompson's "Plum Pudding" model for an atom with most of its mass concentrated into a tiny charged core in its center. *Brody&Brody, The Science Class You Wish You Had

1937 The London Illustrated News had a picture of a wolf bone discovered in Czechoslovakia by Karl Absolom which has 55 notches in groups of 5, the first 25 being separated from the rest by one of double length. Dating from 30,000 BC, this is the earliest record of counting. [Bunt, Jones, Bedient, The Historical Root of Elementary Mathematics, p 2]. *VFR (The head of an ivory Venus figurine was excavated close to the bone.)

1955 The Electronic Numerical Integrator and Computer (ENIAC) retired. After disassembly, parts of this computer were shipped to the Smithsonian for display. *Goldstein, The Computer from Pascal to von Neumann, p. 234–5.
After eleven years of calculating and processing programs, the ENIAC was retired. Designers John Mauchly and J. Presper Eckert had unveiled the machine in February 1946, showing off its 1,000-time improvement in speed over its contemporaries. The ENIAC ran at 5,000 operations a second with a system of plug boards, switches, and punch cards. It occupied 1,000 square feet of floor space. *CHM

1956, the Atomicron, the first atomic clock in the U.S., was unveiled at the Overseas Press Club in New York City. The basis of the timing was the constant frequency of the oscillations of the caesium atom - 9,192,631,830 MHz. It was priced at $50,000. The Atomicron measured 84" high, 22" wide and 18" deep. *TIS

1959 At the New England eclipse of October 2, 1959, Dr. E. H. Land, inventor of the Polaroid Land camera, had accompanied Harvard astronomers on a DC-6 plane that flew above the heavy overcast. On this flight, Dr. Land and his colleagues secured several excellent photographs of the corona, using Polaroid cameras with telephoto lenses. *NSEC



BIRTHS

1568 Marino Ghetaldi (2 Oct 1568, 11 April 1626) was a Croatian mathematician who published work with early applications of algebra to geometry. *SAU His best results are mainly in physics, especially optics, and mathematics. He was one of the few students of François Viète. He took over Viète's work to restore Apollonius' lost works. He followed Pappus's description of the contents of certain lost books and to do this he had to solve the problems which the books were supposed to contain. He published Apollonius redivivus seu restituta Apollonii Pergaei inclinationum geometria and Supplementum Apollonii Galli seu exsuscitata Apollonii Pergaei tactionum geometriae pars reliqua both in Venice in 1607.
* National Maritime Museum
Renowned for the application of algebra in geometry and his research in the field of geometrical optics on which, he wrote 7 works, including the Promotus Archimedus (1603) and the De resolutione et compositione mathematica (1630). He also produced a pamphlet with the solutions of 42 geometrical problems, Variorum problematum colletio, in 1607 and set grounds of algebraization of geometry. His contributions to geometry had been
cited by Dutch physicist Christiaan Huygens and Edmond Halley in England.
Ghetaldić was the constructor of the parabolic mirror (66 cm in diameter), kept today at the National Maritime Museum in London. During his sejourn in Padua he met Galileo Galilei, with whom he corresponded regularly. He was a good friend to the French mathematician François Viète. He was offered the post of professor of mathematics in Leuven in Belgium, at the time one of the most prestigious university centers in Europe.

1791 Aléxis Thérèse Petit (2 Oct 1791, 21 June 1820) was a French mathematician who worked on the theory of heat.*SAU

1825 John James Walker (2 Oct 1825, 15 Feb 1900) The range of Walker's mathematical research was quite impressive. He wrote some articles on theoretical mechanics but his more elaborate papers were on advanced algebra and geometry. Walker was a strong advocate of Hamilton's quaternions and strongly believed that they had not been given as wide a use as they merited. He applied quaternions to a variety of problems, mostly of an elementary nature.
The three most important papers that Walker wrote were on the analysis of plane curves and curved lines. The papers were closely connected and all appeared in the Proceedings of the London Mathematical Society. He wrote further articles on cubic curves and in this area he wrote the memoir On the diameters of cubic curves which was published in the Transactions of the Royal Society in 1889. *SAU

1852 Sir William Ramsay (2 Oct 1852; 23 Jul 1916) Scottish chemist who discovered the "inert gases", neon, krypton and xenon, and co-discovered argon, radon, calcium and barium. Nobel laureate (1904) "in recognition of his services in the discovery of the inert gaseous elements in air, and his determination of their place in the periodic system." Died in High Wycombe, Buckinghamshire.*TIS

1886 Robert Julius Trumpler (2 Oct 1886; 10 Sep 1956) Swiss-born U.S. astronomer who moved to the US in 1915 and worked at the Lick Observatory. In 1922, by observing a solar eclipse, he was able to confirm Einstein's theory of relativity. He made extensive studies of galactic star clusters, and demonstrated (1930) the presence throughout the galactic plane of a tenuous haze of interstellar material that absorbs light generally that dims and reddens the light from of distant clusters. The presence of this obscuring haze revealed how the size of spiral galaxies had been over-estimated. Whereas Harlow Shapley, in 1918, determined the distance to the centre of the Milky Way to be 50,000 light-years away, Trumpler's work reduced this to 30,000 light-years.*TIS

1901 Charles Stark Draper (2 Oct 1901; 25 Jul 1987) American aeronautical engineer, educator, and science administrator who earned degrees from Stanford, Harvard, and MIT then, in 1939, became head of MIT's Instrumentation Laboratory, which was a centre for the design of navigational and guidance systems for ships, airplanes, and missiles from World War II through the Cold War. He developed gyroscope systems that stabilized and balanced gunsights and bombsights and which were later expanded to an inertial guidance system for launching long-range missiles at supersonic jet targets. He was "the father of inertial navigation." The Project Apollo contract for guiding man and spacecraft to the moon was also placed with the Instrumentation Lab. *TIS

1908 Arthur Erdélyi studied in Brno and Prague and came to Scotland before the Second World War to avoid the Nazi invasion of Czechoslovakia. He became a lecturer at Edinburgh and after a period in the USA he returned to Edinburgh as a Professor. He was an expert on Special Functions. He became President of the EMS in 1971. *SAU

1926 Michio Suzuki (October 2, 1926 – May 31, 1998) was a Japanese mathematician who studied group theory.
He was a Professor at the University of Illinois at Urbana-Champaign from 1953 to his death. He also had visiting positions at the University of Chicago (1960–61), the Institute for Advanced Study (1962–63, 1968–69, spring 1981), the University of Tokyo (spring 1971), and the University of Padua (1994). Suzuki received his Ph.D in 1952 from the University of Tokyo, despite having moved to the United States the previous year. He was the first to attack the Burnside conjecture, that every finite non-abelian simple group has even order.
A notable achievement was his discovery in 1960 of the Suzuki groups, an infinite family of the only non-abelian simple groups whose order is not divisible by 3. The smallest, of order 29120, was the first simple group of order less than 1 million to be discovered since Dickson's list of 1900.
He classified several classes of simple groups of small rank, including the CIT-groups and C-groups and CA-groups.
There is also a sporadic simple group called the Suzuki group, which he announced in 1968. The Tits ovoid is also referred to as the Suzuki ovoid. *Wik


DEATHS
1853 Dominique François Jean Arago (26 Feb 1786, 2 Oct 1853) was a French physicist and astronomer who discovered the chromosphere of the sun (the lower atmosphere, primarily composed of hydrogen gas), and for his accurate estimates of the diameters of the planets. Arago found that a rotating copper disk deflects a magnetic needle held above it showing the production of magnetism by rotation of a nonmagnetic conductor. He devised an experiment that proved the wave theory of light, showed that light waves move more slowly through a dense medium than through air and contributed to the discovery of the laws of light polarization. Arago entered politics in 1848 as Minister of War and Marine and was responsible for abolishing slavery in the French colonies. *TIS A really great blog about Arago, With the catchy title, "François Arago: the most interesting physicist in the world!" is posted here. Read this introduction, and you will not be able to resist:
When he was seven years old, he tried to stab a Spanish solider with a lance
When he was eighteen, he talked a friend out of assassinating Napoleon
He once angered an archbishop so much that the holy man punched him in the face
He has negotiated with bandits, been chased by a mob, broken out of prison
He is:
François Arago, the most interesting physicist in the world

1929 Andrei Mikhailovich Razmadze (11 Aug 1889, 2 Oct 1929) His work was on the calculus of variations, continuing work by Weierstrass and Hilbert. The fundamental lemma of the calculus of variations is named after him. He also did important work on discontinuous solutions.*SAU

1933 Philipp Forchheimer (7 Aug 1852, 2 Oct 1933) Austrian hydraulic engineer who made significant studies of groundwater hydrology. Early in his academic career, he worked on problems of soil mechanics. Later, he turned to hydraulic problems, establishing the scientific basis of the discipline by applying standard techniques of mathematical physics - in particular Laplace's equation - to problems of groundwater movement. Laplace's equation had already been well developed for heat flow and fluid flow. Forchheimer extended the preexisting mathematical theory to calculations of groundwater flow. He was also the first to both mathematically and experimentally examine the features of dambreak waves in a rectangular channel (with his PhD student Armin Schoklitsch).*TIS

1962 Boris Yakovych Bukreyev (6 September 1859 – 2 October 1962) was a Russian and Soviet mathematician who worked in the areas of complex functions and differential equations.
In 1889, Bukreyev became a professor of mathematics at the University of Kiev, in Ukraine, Russian Empire. He studied Fuchsian functions of rank zero. He was interested in projective and non-Euclidean geometry. He worked on differential invariants and parameters in the theory of surfaces, being interested in the history of mathematics.*Wik

2006 Paul Richard Halmos​ (March 3, 1916 – October 2, 2006) was a Hungarian-born American mathematician who made fundamental advances in the areas of probability theory, statistics, operator theory, ergodic theory, and functional analysis (in particular, Hilbert spaces). He was also recognized as a great mathematical expositor. In a series of papers reprinted in his 1962 Algebraic Logic, Halmos devised polyadic algebras, an algebraic version of first-order logic differing from the better known cylindric algebras of Alfred Tarski and his students. An elementary version of polyadic algebra is described in monadic Boolean algebra.
In addition to his original contributions to mathematics, Halmos was an unusually clear and engaging expositor of university mathematics. This was so even though Halmos arrived in the USA at 13 years of age and never lost his Hungarian accent. He chaired the American Mathematical Society committee that wrote the AMS style guide for academic mathematics, published in 1973. In 1983, he received the AMS's Steele Prize for exposition. Some of his classics were:
How to read mathematics
How to write mathematics
How to speak mathematics.
In the American Scientist 56(4): 375–389, Halmos argued that mathematics is a creative art, and that mathematicians should be seen as artists, not number crunchers. He discussed the division of the field into mathology and mathophysics, further arguing that mathematicians and painters think and work in related ways.
Halmos's 1985 "automathography" I Want to Be a Mathematician is an account of what it was like to be an academic mathematician in 20th century America. He called the book “automathography” rather than “autobiography”, because its focus is almost entirely on his life as a mathematician, not his personal life. The book contains the following quote on Halmos' view of what doing mathematics means:
“ "Don't just read it; fight it! Ask your own questions, look for your own examples, discover your own proofs. Is the hypothesis necessary? Is the converse true? What happens in the classical special case? What about the degenerate cases? Where does the proof use the hypothesis?”
In these memoirs, Halmos claims to have invented the "iff" notation for the words "if and only if" and to have been the first to use the “tombstone” notation to signify the end of a proof, and this is generally agreed to be the case. The tombstone symbol ∎ (Unicode U+220E) is sometimes called a halmos. *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

Tuesday, 1 October 2013

I said it, but I don't believe it... lies my blog told me


The 280th day of the year is upon us, and as I always post an arithmetic or mathematical piece of trivia about the day of the year, I used the same quote from Wikipedia that I had used last year (and yes it's still there this year, on Wikipedia and my blog, while I figure out if I really just don't understand, or if it is wrong... hence this blog)

So here is what it (Wikipedia) and I (my blog) said: "There are 280 plane trees with ten nodes. As a consequence of this, 18 people around a round table can shake hands with each other in non-crossing ways, in 280 different ways (this includes rotations)."

Ok, so I see a three-fold task, 1) is there a relation between the number of plane trees with n nodes and (apparently) the number of ways that 2(n-1) people around a table can shake hands without crossing arms, 2) independent of the relationship between the two ideas, can I figure out how many plane trees there are with ten nodes, and 3) the same about the number of handshakes by 18 people around a table without crossing hands.

In the interest of drawing better mathematical talent to give me assistance, I will expose my attempts to reason through these questions by exposing my limited understanding in this blog... Corrections and contributions are welcomed.

So for part 1 and 2, I used Wikipedia's definition that "An ordered tree or plane tree is a rooted tree for which an ordering is specified for the children of each vertex." I found a nice article from Australia that uses the rooted tree with the root down, but otherwise counts the number of, "rooted planer trees" and the numbers for planer trees with 3, 4, and 5 nodes had respectively, 2, 5 and 14 different trees.... Holy Molley Captain Marvel, those I recognize as Catalan numbers...could it be??? yep, the number of trees with 6 nodes was 42. So All I had to do was check the number of possible handshakes for 2(3-1), 2(4-1) etc and see if they too were Catalan numbers. Maybe these were both one of the myriad of combinatorial objects counted by the Catalan sequence.

It took me a short while to decide how to attack the handshakes, but I settled on an even number of dots equally spaced around a circle. To avoid having any two chords (handshakes) intersect, it seemed that when points a and b were connected, there must be an even number of handshakes on each side of the circle divided by the chord. If not, they could not all shake hands. So I could divide the n points and repeat the problem on a smaller n on each side of the dividing chord. This seemed to require a recursive process so I reduced the problem down to 2 points. For n=2 there could only be 1 handshake, For n= 4 points, I could visually see that there would only be 2 possible ways,

To divide the graph with six points, I could either have no points on the left of the division, and four on the right, OR two on the left and two on the right, OR four on the left and none on the right. If I added the number of cases with 4 on the right to the number of cases with two on the left times the number with two on the right, plus the number with 4 on the left, I would know the number for six... I needed some notation here so I called the H(n) for the number of handshakes, with H(2)=1, H(4) = 2... so the expression for H(6) would be H(4) + H(2)*H(2)+ H(4) = 2+1+2 = 5... Eureka, a Catalan Number. Drawing the graph of H(6) convinced me that I was on the right track.

The upper two images show Point I connecting to a neighbor on his anti-clockwise side leaving the two divisions of the remaining four. The third and fourth show the clockwise neighbor choice leaving H(4)=2 choices again, and the fifth shows the connection with the opposite side, giving only H(2)*H(2) = 1 choice for a total of five. 

It seemed the two ideas were related after all so I look at the OEIS web page to see what they had about Catalan numbers . They give, under the Catalan sequence "a(n) is the number of ordered rooted trees with n nodes, not including the root."  So Catalan(4) would give the number of trees for a ordered rooted tree with 5 nodes, 14.     See the Conway-Guy reference where these rooted ordered trees are called plane bushes."  So Catalan(4) would give the number of trees for a ordered rooted tree with 5 nodes, 14.
Farther down there was a note that a(n) is the number of ways of joining 2n points on a circle to form n non-intersecting chords. So H(8) would be a(4)= 14 (Hey that was my approach, I was feeling a little more clever now, and sorry that I ever doubted good ol' Wikipedia).
But then.....
For parts 2) and 3) of the question, it seemed that the number of handshakes with 18 people would be H(18) = Catalan(9) and the OEIS lists Catalan(9) as 4862, which my rough arithmetic background told me might be way more than 280????

And the number of ordered planted trees with 10 nodes would also be Catalan(9) which is still 4862 and still TOOO big to be 280..

SOOOO now I need someone out there who understands this to confirm that what I have above is correct or how I am misinterpreting the Wikipedia article. It didn't give a reference, so I'm not sure who to verify their numbers against.

Ummm HELP!

On This Day in Math - October 1



Scientists have one thing in common with children: curiosity. To be a good scientist you must have kept this trait of childhood, and perhaps it is not easy to retain just one trait. A scientist has to be curious like a child; perhaps one can understand that there are other childish features he hasn't grown out of.
~Otto Robert Frisch


The 274th day of the year; 274 is a tribonacci number..The tribonacci numbers are like the Fibonacci numbers, but instead of starting with two predetermined terms, the sequence starts with three predetermined terms and each term afterwards is the sum of the preceding three terms. The first few tribonacci numbers are 0, 0, 1, 1, 2, 4, 7,


EVENTS

1386 University of Heidelberg founded. The Ruprecht-Karls-Universität Heidelberg (Heidelberg University, Ruperto Carola) is a public research university located in Heidelberg, Baden-Württemberg, Germany. It is the oldest university in Germany and was the fourth university established in the Holy Roman Empire. A coeducational institution since 1899, today Heidelberg consists of twelve faculties and offers degree programs at undergraduate, graduate and postdoctoral levels in some 100 disciplines. *Wik

1610 Lodovico Cigoli writes to Galileo to inform him that Father Christoph Clavius SJ, the senior mathematician at the Collegio Romano, had said that if the telescope revealed four
new ‘planets’ around Jupiter to Galileo, then Galileo must have put them in the telescope to begin with. Two months later, Clavius had observed Jupiter’s moons himself. *Albert Van Helden, Galileo and the telescope, The origins of the telescope, Royal Netherlands Academy of Arts and Sciences, Amsterdam 2010

1658 The closing date for Pascal’s prize problems on the cycloid. (T. Christie advised me that some give the date as Oct 2).  A toothache earlier that year caused him to return to mathematics and to study the cycloid. In 1654, late in the evening Pascal experienced a religious ecstasy that called him to give up his intermittent interest in mathematics and to devote his time to religious contemplation. For years he devoted no time to mathematics. Then one night, unable to sleep because of an abscessed tooth, Pascal began to think about some problems about the cycloid. His pain disappeared and he interpreted this as a sign that God was pleased by his mathematical studies. In a brief time he completed the investigationof the cycloid. Then he established a contest about the cycloid with himself and Roberval as the judges. The three problems he asked were:
cycloidPascal.png
1. Find the area and the center of gravity of the region BCD bounded by the cycloid, the horizontal line BC and the axis of symmetry AD.
2. Find the volume and center of gravity of the solids obtained by revolving the region BCD about AD and about BC.
3. For the solids in the previous question, find the center of gravity of the solids formed when each is cut by a plane parallel to its axis of revolution.
Only two contestants submitted solutions. No prize was awarded as the judges declared that the solutions were either incomplete or incorrect. Pascal then published his own results in a paper entitled "L'Histoire de la Roulette".  It is worth noting that all these investigations of the cycloid occurred before Newton and Leibnitz' work on the calculus!  *Historical Modules for the Mathematical Classroom There is a famous statue by Pajou in the Louvre of Pascal in which he is contemplating the Roulette (cycloid). (And in this photo, I am contemplating him contemplating the roulette) More on the cycloid, including a close up of the tablet in the statue is here.

1670 James Gregory writes to John Collins, with the first use of what will come to be called the Newton-Gregory interpolation formula. He includes in the letter two enclosures showing how to apply his method to series for sines and logarithms. *Beery & Stedall, Thomas Harriot’s Doctrine of Triangular Numbers, pg 51-52

1752  A letter of Benjamin Franklin written on October 1st, to Mr. Peter Collinson, FRS concerning an electrical kite, was read before the society on Dec 21.  Franklin describes the construction of the kite from two light strips of cedar and a large thin silk  handkerchief, 

1831 Michael Faraday discovers induced electric current using a helix made of two coils each of 203 feet of insulated copper wire. "A sudden jerk was perceived when the battery communication was made and broken... it was one way when made, and the other when broken." *A history of physics in its elementary branches By Florian Cajori

1842 Arthur Cayley's acceptance to Trinity was announced on this day. He was twenty-one years old and accepted on his first sitting, a rare event. He was the youngest man admitted to Trinity in the 19th Century. * A. J. Crilly, Arthur Cayley: Mathematician Laureate of the Victorian Age

1847 Maria Mitchell sees a comet... the first woman astronomer in the United States discovered a comet. On this night in the Autumn of 1847, Maria looked at the sky through the telescope in her homemade observatory at Nantucket, Mass. and saw a star five degrees above the North Star where there had been no star before. She had memorized the sky and was sure of her observation. It occurred to her that this might be a comet. Maria recorded the presumed comet's coordinates. The next night the star moved again. This time she was sure it was a comet. For this discovery, she was awarded a gold medal by the king of Denmark. She became the first woman elected to the American Academy of Arts and Sciences. *TIS

1861 On Oct 1, a seemingly depressed Charles Darwin writes, "My Dear Lyell, ... I am very poorly today & very stupid & hate everybody & everything. One lives only to make blunders.–... I am
Ever yours
C. Darwin

1891 On Oct 1 Stanford University​ opened its doors after six years of planning and building. The prediction of a New York newspaper that Stanford professors would "lecture in marble halls to empty benches" was quickly disproved. The first student body consisted of 555 men and women, and the original faculty of 15 was expanded to 49 for the second year. The university’s first president was David Starr Jordan​, a graduate of Cornell, who left his post as president of Indiana University​ to join the adventure out West.
The Stanfords engaged Frederick Law Olmsted​, the famed landscape architect who created New York’s Central Park​, to design the physical plan for the university. The collaboration was contentious, but finally resulted in an organization of quadrangles on an east-west axis. Today, as Stanford continues to expand, the university’s architects attempt to respect those original university plans. *Stanford Univ Web page

1895  On the first of October 1895, the first German institute of insurance science was founded at the University of Göttingen, as a result of joint efforts of Felix Klein (1849-1825) and his fellow student Ludwig Kiepert (1846-1934), who was then chairman of the Prussian Civil Service Association (today called Hannover Life Insurance).This was the first institute in Germany in which a curriculum in actuarial mathematics, insurance law, and insurance economics was offered. Successful studies led to the degree “Versicherungsverständiger” (insurance expert). The institute was divided into a mathematical section and an administrative section, and its first chairman was Wilhelm Lexis. *From Center for Statistics, History of Statistics in Gottingen.

1907 Delegates from 310 Esperanto societies throughout the world met to elect a committee to modify the language. Louis Couturat, influenced by Leibniz’s thought on the construction of a logical universal language, was elected one of the secretaries.  *VFR

1934 Paul Erdos stops in Cambridge to visit with mathematical friends, particularly Harrold Davenport and Richard Rado, on his way to a position in Manchester. *Bruce Schechter, My Brain is Open: The Mathematical Journeys of Paul Erdos

1954 IBM announced is 705 EDP, part of its 700 series of mainframe computers. A business-oriented machine, the 705 had magnetic core memory.*CHM

1969 Concorde goes Mach 1 In 1969, the prototype French-built Concorde broke the sound barrier for the first time. The inaugural flight of the aircraft had taken place on 2 Mar 1969 in Toulouse, France, and its first commercial flight was on 21 Jan 1976. It was the first plane in the world to be entirely controlled by computer. As the only supersonic passenger aircraft, the Anglo-French Concorde remains a brilliant technological achievement, though its impact on international air travel has been limited by the high cost of buying and operating the aircraft. There was also widespread opposition from environmental groups on the grounds of the Concorde's noise on takeoff and its fuel consumption. Only British Airways and Air France have operated the aircraft. *TIS

1988   The game Connect Four Solved first by James D. Allen (Oct 1, 1988), and independently by Victor Allis (Oct 16, 1988). First player can force a win. Strongly solved by John Tromp's 8-ply database (Feb 4, 1995). Weakly solved for all boardsizes where width+height is at most 15 (Feb 18, 2006). *Wik

2012 With God's grace, Dame Kathleen Ollerenshaw will awake for her 100th birthday today. Happy Birthday to a Grand-Ol-Dame, and may a puzzle occupy her thoughts. (See 1912 Births below).



BIRTHS

1535 Giambattista della Porta (? Oct 1535 - 4 Feb 1615) Italian natural philosopher, experimenter and mathematician, though he also sought the miraculous or magical. He studied optics, including refraction (De refractione, 1593). Porta did not invent the telescope, regardless of his published claim. He was the first to propose adding a convex lens to the camera obscura, and first to recognize the heating effect of light rays. He wrote on cryptography in De furtivis literarum (1563), and his other books included mechanics, squaring the circle, description of a steam engine in De spiritali (1606). He formed the society, Accademia dei Segreti, dedicated to discussing and studying nature, meeting at his home, until closed by the Inquisition (about 1578). *TIS

1671 Luigi Guido Grandi was an Italian Jesuit who worked on geometry and hydraulics.Grandi was the author of a number of works on geometry in which he considered the analogies of the circle and equilateral hyperbola. He also considered curves of double curvature on the sphere and the quadrature of parts of a spherical surface.
In 1701 Grandi discussed the conical loxodrome, the curve that cuts the generators of a cone of revolution in a constant angle. He studied the curve the Witch of Agnesi in 1703. In fact his work of 1703 is important in introducing Leibniz's calculus into Italy.
In 1728 Grandi published Flores geometrici a work in which he defines the clelie curve. He named the curve after Countess Clelia Borromeo and dedicated his book to her. If the longitude and colatitude of a point P on a sphere is denoted by θ and φ and if P moves so that θ = m φ, where m is a constant, then the locus of P is a clelie. Grandi also applied the term "clelies" to the curves determined by certain trigonometric equations involving the sine function
a sin θ = b sin mφ
a sin θ = a - b sin mφ
Grandi also worked on hydraulics and was involved with a number of projects such as ones to drain the Chiana Valley and the Pontine Marshes. He also published a number of works on mechanics and astronomy. His practical work on mechanics included experimenting with a steam engine. *SAU 
He is noted for the roses that he introduced. His idea was to find a geometrical definition of curves which resemble flowers. These curves are still part of our calculus courses, except now we use polar coordinates to define them.*VFR

1873 Alfreds Arnolds Adolfs Meders (1 Oct 1873 , 1944) Meders worked on differential geometry and mathematical analysis. He often published papers written in German, in German journals. For example he published the following three papers in Crelle's Journal: Über einige Arten Singularer Punkte von Raumkurven (1896); Zur Theorie der singularen Punkte einer Raumkurve (1899); and Analytische Untersuchung singularer Punkte von Raumkurven (1910). In Monatshefte für Mathematik he published: Über die Determinante von Wronski (1906); and Zur Differentiation bestimmter Integrale nach einem Parameter (1911).
Meders was also interested in the history of mathematics and he wrote an important paper Direkte und indirekte Beziehungen zwischen Gauss und der Dorpater Universität (Direct and indirect connections between Gauss and the University of Dorpat) in 1928. His interests went outside mathematics and he sometimes lectured on astronomy, meteorology and biology where he had a special interest in birds. *SAU

1898 Béla Kerékjártó (October 1, 1898, –June 26, 1946) was a Hungarian mathematician who wrote numerous articles on Topology. He earned his Ph.D. degree from the University of Budapest. He taught at the Faculty of Sciences of the University of Szeged from 1922, and at the University of Budapest from 1938. In 1923, he published one of the first books on Topology; Hermann Weyl wrote that this book completely changed his views of the subject.*Wik

1904 Otto Robert Frisch (1 Oct 1904; 22 Sep 1979) Austrian-British nuclear physicist, born in Vienna, who, with his aunt Lise Meitner, described the division of neutron-bombarded uranium into lighter elements. He named the process fission, borrowing a term from biology (1939). At the time, Meitner was working in Stockholm and Frisch (1934-39) at Copenhagen under Niels Bohr, who brought their observation to the attention of Albert Einstein and others in the United States. He did research with James Chadwick 1940-43, and was head of the Critical Assembly Group on the Los Alamos project 1943-46. After World War II, Frisch became a science writer on atomic physics for the layman. *TIS

1911 Zhou Weiliang (simplified Chinese: (October 1, 1911– August 10, 1995) was a Chinese mathematician born in Shanghai, known for his work in algebraic geometry.
He was a student in the USA, graduating from the University of Chicago in 1931. In 1932 he attended the University of Göttingen, then transferring to Leipzig where he worked with van der Waerden. They produced a series of joint papers on intersection theory, introducing in particular the use of what are now generally called Chow coordinates (which were in some form familiar to Arthur Cayley).
He married Margot Victor in 1936, and took a position at the National Central University in Nanjing. His mathematical work was seriously affected by the wartime situation in China. He taught at the National Tung-Chi University in Shanghai in the academic year 1946–47, and then went to the Institute for Advanced Study in Princeton, where he returned to his research. From 1948 to 1977 he was a professor at Johns Hopkins University. *Wik

1912 Dame Kathleen Mary Ollerenshaw, née Timpson, DBE (1 October 1912, ) is a British mathematician and politician. Deaf since the age of eight, she loved doing arithmetic problems as a child. As a young woman, she attended St Leonards School and Sixth Form College in St Andrews, Scotland where today the house of young male boarders is named after her. At the age of 19, she gained admittance to Somerville College, Oxford to study mathematics. She completed her doctorate at Somerville in 1945 on "Critical Lattices" under the supervision of Theo Chaundy. She wrote five original research papers which were sufficient for her to earn her DPhil degree without the need of a formal written thesis.
Ollerenshaw served as a Conservative Councillor for Rusholme for twenty-six years (1956–1981), was Lord Mayor of Manchester (1975–1976), and the prime motivator in the creation of the Royal Northern College of Music. She was made a Freeman of the City of Manchester and was an advisor on educational matters to Margaret Thatcher's government in the 1980s.
She has published at least 26 mathematical papers, her best-known contribution being to most-perfect pandiagonal magic squares. An annual public lecture at the School of Mathematics, University of Manchester is named in her honour.
An amateur astronomer, Ollerenshaw donated her telescope to Lancaster University, and an observatory there bears her name. She is an honorary member of the Manchester Astronomical Society and held the post of Vice President for a number of years. *Wik A wonderful article about her approaching her 100th birthday is in Scientific American.



DEATHS

1768 Robert Simson (14 October 1687 – 1 October 1768) was a Scottish mathematician and professor of mathematics at the University of Glasgow. The pedal line of a triangle is sometimes called the "Simson line" after him. Edmond Halley suggested to him that he might devote his considerable talents to the restoration of the work of the early Greek geometers, such as Euclid and Apollonius of Perga. These are works that only survive in abbreviated accounts given by later mathematicians such as Pappus of Alexandria. He first studied Euclid's so-called porisms. Playfair's 1792 definition of porism is "a proposition affirming the possibility of finding such conditions as will render a certain problem indeterminate, or capable of innumerable solutions."
Simson's work on Euclid's porisms was published in 1723 in the Philosophical Transactions of the Royal Society, and his restoration of the Loci Plani of Apollonius appeared in 1749. Further work of his on porisms and other subjects including logarithms was published posthumously in 1776 by Lord Stanhope at his own expense. Simson also set himself the task of preparing an edition of Euclid's Elements in as perfect a form as possible, and his edition of Euclid's books 1-6, 11 and 12 was for many years the standard text and formed the basis of textbooks on geometry written by other authors. The work ran through more than 70 different editions, revisions or translations published first in Glasgow in 1756, with others appearing in Glasgow, Edinburgh, Dublin, London, Cambridge, Paris and a number of other European and American cities. Recent editions appeared in London and Toronto in 1933 under the editorship of Isaac Todhunter, and in São Paolo in 1944. Simson's lectures were delivered in Latin, at any rate at the beginning of his career. His most important writings were written in that language, however, his edition of Euclid, after its first publication in Latin, appeared in English, as did a treatise on conic sections that he wrote for the benefit of his students.
the Simson line does not appear in his work but Poncelet in Propriétés Projectives says that the theorem was attributed to Simson by Servois in the Gergonne's Journal. It appears that the theorem is due to William Wallace.
The University of St Andrews awarded Simson an honorary Doctorate of Medicine in 1746.
In 1753 Simson noted that, as the Fibonacci numbers increased in magnitude, the ratio between adjacent numbers approached the golden ratio, whose value is
(1 + √5)/2 = 1.6180 . . . . *SAU

1924 John Edward Campbell is remembered for the Campbell-Baker-Hausdorff theorem which gives a formula for multiplication of exponentials in Lie algebras. *SAU

1972 Francisco José Duarte (6 Jan 1883, 1 Oct 1972) Duarte's most important work in mathematics was done in algebra, number theory and mathematical analysis. His first work in mathematics was about which he presented to the Paris Academy of Sciences in 1907. He published papers on the general solution of a diophantine equation of the third degree x3 + y3 + z3 - 3xyz = v3, simplified Kummer's criterion and gave a simple proof of the impossibility of solving the Fermat equation x3 + y3 + z3 = 0 in nonzero integers. He also observed that the interpolation formula of Everett is a consequence of the interpolation formula of Gauss. In 1908 he published an article where he calculated π to 200 decimal places.
His main three books are: Monograph on the numbers π and e. Historical and bibliographical notes (Spanish) (Bol. Acad. Cien. Fis. Mat. Nat. 11(1948)), with 27 chapters on 250 pages, which contains more information on π and e than has ever before been collected in one place; Lessons on Infinitesimal Analysis (Caracas 1943, 606 pp.) (Spanish) containing material from courses in analysis at UCV during his first three or four years there; and Bibliography of Euclid, Archimedes, Newton (Acad. Cien. Fis. Mat. Nat., Caracas 1963, 163 pp.) (Spanish) which was also done in the 19th century.
Many mathematicians are interested in recreational mathematics. Duarte also contributed to that part of mathematics and proposed problems and solutions to the American Mathematical Monthly for several years, and also to the journal Ciencia y Ingenieria (Science and Engineering) published in Mérida. *SAU

1990 John Stewart Bell​ FRS (28 June 1928 – 1 October 1990) was a physicist from Northern Ireland (Ulster), and the originator of Bell's theorem, a significant theorem in quantum physics regarding hidden variable theories.*Wik

1996 Herbert Karl Johannes Seifert (May 27, 1907– October 1, 1996) was a German mathematician known for his work in topology.


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