Aleksandr Korkin
Alexander Nikolayevich Korkin (Russian Александр Николаевич Коркин; * 19 Februarjul / March 3 1837greg in Schidowinowo, Vologda Province, .. .. † 19 Augustjul / September 1 1908greg in St. Petersburg) was a Russian mathematician who has the right to mainly employed with partial differential equations and geometry of numbers.
Life and work
Korkins father was indeed a prosperous farmer and businessman, while also serf of the Vologda province, about 700 kilometers east of St. Petersburg. He was educated in the provincial capital of Vologda Alexander Iwanizki, a student of Bunjakowski. From 1847 he attended the local grammar school, after his father had ransomed. He was a very good student and graduated in 1854 at the University of St. Petersburg in Chebyshev, Osip Ivanovich Somov and Bunjakowski mathematics and physics. Since his father had recently died, leaving him penniless, he had to finance through private lessons for a living. An essay on the calculus of variations brought him in 1856 the gold medal of the University. In 1858 he graduated as a future mathematics teacher and began after he redeemed himself with a further sum of money, to teach at the military academy. In 1860 he received his doctorate in Chebyshev and began after he won a contest to to teach at the university. Because of political unrest, the university was shorted out and Korkin was sent abroad to study further. In 1862 he visited Paris, where he heard Joseph Liouville, Gabriel Lamé and Joseph Bertrand and a year later Ernst Eduard Kummer and Karl Weierstrass in Berlin. In 1867 he qualified as a professor in St. Petersburg with a thesis on partial differential equations. In 1868 he became an associate professor at the University, 1873 Professor, a position he held until his death. At the same time he taught Analysis at the Naval Academy from 1864 to 1900 (succeeding Bunjakowski ).
Korkin worked primarily on partial differential equations, but is now mainly used for working with his students Yegor Ivanovich Zolotarev via integral positive definite quadratic forms in several variables known (1872, 1873, 1877). They solved a problem of Charles Hermite, who asked for the upper bounds for the minima of such forms as a function of the coefficients and, for a fixed discriminant ( determinant of the symmetric coefficient matrix ). In her first work of 1872 on quadratic forms in four variables they disproved a conjecture of Hermite this upper bound and gave instead to the upper bound. Square shapes whose minima were relative maxima ( again, depending on the coefficient ) of them were referred to extremal. For quadratic forms in variables they showed in 1873 that Hermites suspected upper bound actually was the barrier for the minima of some extremal forms, but not all. Korkin also dealt with iteration, especially with the Abelian functional equation.
After Korkin and Solotaryov a definition for the reduced form a basis of a lattice is named ( an alternative definition comes from Hermann Minkowski ).
Among his students was one of Alexei Nikolaevich Krylov, who also became his successor at the Naval Academy, Dmitry Nikolaevich Delone Grawe and Boris.