## Sunday 19 November 2023

### On This Day in Math - November 19

A visitor to Niels Bohr's country cottage, noticing a horseshoe hanging on the wall, teasing the eminent scientist about this ancient superstition. 'Can it be true that you, of all people, believe it will bring you luck?'
'Of course not,' replied Bohr, 'but I understand it brings you luck whether you believe it or not.'

The 323rd day of the year; If you put drew every possible path from (0,0) to (8,0) that never dropped below the x-axis using only unit vectorial moves with slopes of 1, 0, or -1 there are 323 possible paths. (alternatively this is the number of different ways of drawing non-intersecting chords on a circle with eight points- this is deceptive because it counts each way of drawing a single chord, and drawing no chords at all, students might want to count how many ways this can be done using four chords.) These are called Motzkin numbers, after Theodore Motzkin.

323 is the sum of nine consecutive primes 323 = 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 *Derek Orr

323 is a palindrome and also the smallest composite number n that divides the (n+1)st Fibonacci number. *What's Special about this Number

e is approximately 2 + 232 / 323.

EVENTS
On this day in 1812 Jean Victor Poncelet was captured after being left for dead on the battlefield following the Battle of Krasnoi, near Smolensk, while with Napoleon's army retreating from Moscow. He profited from captivity (until his release in June 1814) by resuming his study of mathematics, and while in Russia he did important work on projective geometry.

1857 Arthur Cayley opens a letter to J. J. Sylvester with, "I have just obtained a theorem that appears to be very remarkable." The theorem would be the centerpiece of his Memoire on the Theory of Matrices. The theorem showed that a matrix was the solution of its own characteristic equation. *A. J. Crilly, Arthur Cayley: Mathematician Laureate of the Victorian Age

1982 Science has an article describing Friedman’s version of Kruskal’s theorem. The important thing is that this is a mathematical (rather than metamathematical) statement independent of arithmetic. *VFR

1992   Sonic The Hedgehog 2 Is Released    Sega releases the second  game for its top franchise, Sonic the Hedgehog, for the Sega Genesis platform. Genesis was running second to the Super Nintendo Entertainment System with its franchise creations such as Mario and Starfox. Sonic would be the leading character for Sega platforms throughout the 1990s, and would eventually be licensed to other companies once Sega stopped producing it’s own platforms with its Dreamcast system. *CHM

2010 Experts confirmed that the remains of the 16th-century Danish astronomer Tycho Brahe, his wife and another eight people, including five children, were buried in Prague's Church of Our Lady before Tyn. The tin coffin, tied up with a red ribbon, was deposited in the tomb in the overcrowded church that afternoon preceded by a church service celebrated by Prague Archbishop Dominik Duka and including prayers in Czech and Danish. *Wik The grave had been previously opened 1901, on the three hundredth anniversary of his death, the bodies of Tycho Brahe and his wife Kirstine were exhumed in Prague. They had been embalmed and were in remarkably good condition, but the astronomer’s artificial nose was missing, apparently filched by someone after his death. It had been made for him in gold and silver when his original nose was sliced off in a duel he fought in his youth at Rostock University after a quarrel over some obscure mathematical point.

BIRTHS

1894 Heinz Hopf (19 Nov 1894 in Gräbschen (near Breslau), Germany (now Wrocław, Poland) - 3 June 1971 in Zollikon, Switzerland) work was in algebraic topology. He studied vector fields and extended Lefschetz's fixed point formula. He also studied homotopy classes and defined what is now known as the 'Hopf invariant'.*SAU

1900 Mikhail Lavrentev (19 Nov 1900 in Kazan, Russia
- 15 Oct 1980 in Moscow, Russia) remembered for an outstanding book on conformal mappings and he made many important contributions to that topic.*SAU

1901 Nina Karlovna Bari (November 19, 1901, Moscow – July 15, 1961, Moscow) was a Soviet mathematician known for her work on trigonometric series.  She is also well-known for two textbooks, Higher Algebra and The Theory of Series.
She studied trigonometric series and functions under the tutelage of Nikolai Luzin, becoming one of his star students. She presented the main result of her research to the Moscow Mathematical Society in 1922—the first woman to address the society.
She was killed by a train in the Moscow Metro, and her colleagues speculated that she committed suicide, prompted by the death of her mentor Nikolai Luzin ten years earlier, a man who may have been her lover.*Wik

1907 Adrien Albert (19 November 1907, Sydney - 29 December 1989, Canberra) was a leading authority in the development of medicinal chemistry in Australia. Albert also authored many important books on chemistry, including one on selective toxicity.
He was awarded BSc with first class honours and the University Medal in 1932 at the University of Sydney. He gained a PhD in 1937 and a DSc in 1947 from the University of London. His appointments included Lecturer at the University of Sydney (1938-1947), advisor to the Medical Directorate of the Australian Army (1942-1947), research at the Wellcome Research Institute in London (1947-1948) and in 1948 the Foundation Chair of Medical Chemistry in the John Curtin School of Medical Research at the Australian National University in Canberra where he established the Department of Medical Chemistry. He was a Fellow of the Australian Academy of Science.
He was the author of Selective Toxicity: The Physico-Chemical Basis of Therapy, first published by Chapman and Hall in 1951.
The Adrien Albert Laboratory of Medicinal Chemistry at the University of Sydney was established in his honour in 1989.[1] His bequest funds the Adrien Albert Lectureship, awarded every two years by the Royal Society of Chemistry *Wik

1918 Hendrik Christoffel van de Hulst (19 Nov 1918; 31 Jul 2000) Dutch astronomer who predicted theoretically (1944) that in interstellar space the amount of neutral atomic hydrogen, which in its hyperfine transition radiates and absorbs at a wavelength of 21 cm, might be expected to occur at such high column densities as to provide a spectral line sufficiently strong as to be measurable. Shortly after the end of the war several groups set about to test this prediction. The 21-cm line of atomic hydrogen was detected in 1951, first at Harvard University followed within a few weeks by others. The discovery demonstrated that astronomical research, which at that time was limited to conventional light, could be complemented with observations at radio wavelengths, revealing a range of new physical processes.*TIS

DEATHS

1672 John Wilkins FRS (1 January 1614 – 19 November 1672) was an English clergyman, natural philosopher and author, as well as a founder of the Invisible College and one of the founders of the Royal Society, and Bishop of Chester from 1668 until his death. Along with his inventions (almost all of which were destroyed in the Great Fire) and assorted writings on philosophy, mathematics, and cryptography, John Wilkins distinguished himself by planning the first lunar expedition.(in the 17th century??? Yes… learn more here)
He wrote for the common reader the Discovery (1638) and the Discourse (1640) which showed how reason and experience supported Copernicus, Kepler and Galileo rather than Aristotlian or literal biblical doctrines. In 1641, he anonymously published a small but comprehensive treatise on cryptography. In Mathematical Magick (1648) he described and illustrated the balance lever, wheel, pulley, wedge and screw in a part called "Archimedes or Mechanical Powers" and in a second part "Daedalus or Mechanical Motions" such strange devices as flying machines, artificial spiders, a land yacht, and a submarine. *Wik

1998 Tetsuya Theodore Fujita(23 Oct 1920, 19 Nov 1998) was a Japanese-American meteorologist who increased the knowledge of severe storms. In 1953, he began research in the U.S. Shortly afterwards, he immigrated and established the Severe Local Storms Project. He was known as "Mr. Tornado" as a result of the Fujita scale (F-scale, Feb 1971), which he and his wife, Sumiko, developed for measuring tornadoes on the basis of their damage. Following the crash of Eastern flight 66 on 24 Jun 1975, he reviewed weather-related aircraft disasters and verified the downburst and the microburst (small downburst) phenomena, enabling airplane pilots to be trained on how to react to them. Late in his career, he turned to the study of storm tracks and El Nino. *TIS

*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