Wednesday, December 9, 2009

December 9 - Nikolai Luzin

Nikolai Nikolaevich Luzin Born on December 9, 1883 (Irkutsk, Russia), he is recognized among the founders of descriptive set theory. His Ph.D. is from Moscow State University (1915, "The Integral and Trigonometric Series", advisor Dimitri Egorov). The encounter with Pavel Florensky and his religious thought played an important role in helping Luzin overcome the personal crisis he went through in his early 20's. Later on, he led the research group known as Luzitania, together with Egorov. Some references: Math Genealogy Project, Mac Tutor biography. He suffered persecution, being considered an "enemy under the mask of a Soviet citizen". He died on January 28, 1950.

Tuesday, December 8, 2009

Hindu-Arabic numerals in Europe

Here is a passage from "Liber Abaci" (1202) featuring the Hindu-Arabic numerals:

"Novem figure indorum he sunt 9 8 7 6 5 4 3 2 1 Cum his itaque novem figuris, et cum hoc signo 0, quod arabice zephirum appellatur, scribitur quilibet numerus, ut inferius demonstratur." Leonardo Pisano (Fibonacci) - Liber Abaci

However, it appears that the European debut of the Hindu-Arabic numerals is in an illuminated manuscript dated 976 ("Codex Vigilanus") - though without the zero:

Obviously, their use becomes widespread after the invention of printing.