Jørgen Pedersen Gram

Jørgen Pedersen Gram (born June 27, 1850 in Nustrup near Haderslev , † April 29, 1916 in Copenhagen ) was a Danish mathematician .

Life

Gram was the son of a farmer and went to the Ribe Cathedral School . From 1868 he studied mathematics in Copenhagen, with a diploma in 1873. A year later his first publication on invariant theory appeared in the Tidskrift for Mathematik and the Mathematische Annalen . From 1875 he worked for the Hafnia insurance company . In 1879 he received his PhD for a publication on infinite series in the least squares method (published in Crelle's Journal for Pure and Applied Mathematics ).

In addition to purely mathematical work, he also published work on forestry, where he pursued both the mathematical side, but also carried out his own experiments with trees to adapt his models. In 1884 he founded his own insurance company Skjold , of which he was director until 1910. But he also continued to work in a leading position at Hafnia Insurance and was on its board from 1895 to 1910. From 1910 to 1916 he was chairman of the Danish Insurance Council.

Although Gram did not give lectures at the university, he gave lectures to the Danish Mathematical Society and was editor of the Tidskrift for Mathematik from 1883 to 1889 . He also reviewed Danish mathematical work for the yearbook on the progress of mathematics .

Gram had been married since 1879 and after the death of his first wife in second marriage from 1896. He had been a member of the Danish Academy of Sciences since 1888, was its treasurer for many years and received its gold medal in 1884 for a work on prime number distribution. Gram died on his way to a meeting of the Danish Academy of Sciences after being hit by a bicycle.

His achievements include the Gram-Schmidt orthogonalization method (which was already known, for example Laplace and Cauchy ) and his series representation of the Riemann zeta function . In particular, he was one of the first to calculate the nontrivial zeros of the Riemann zeta function with higher numerical accuracy. In 1903 he published his results for the first fifteen nontrivial zeros. As a result of his investigations, Gram points , Gram blocks and Gram's rule for these zeros were named.

In the field of number theory he corresponded with Ernst Meissel . In his honor in the theory of lattices , the matrix of the pairwise scalar products of all vectors of a basis is called the Gram matrix and its determinant is called the Gram determinant .

Web links

Commons : Jørgen Pedersen Gram - collection of images

John J. O'Connor, Edmund F. Robertson : Jørgen Pedersen Gram. In: MacTutor History of Mathematics archive .

Individual evidence

↑ Gram: Sur les zeros de la fonction de Riemann ${\ displaystyle \ zeta (s)}$ , Acta Mathematica, Volume 27, 1903, pp. 289-304
^ Gram's Law in Eric Weissteins MathWorld
↑ E. Karkoschka, P. Werner: Some exceptions to Rosser's rule in the theory of the Riemann zeta function , Computing 27 (1981), pp. 57-69
^ Henri Cohen : A course in computational algebraic number theory , Springer 1993, p. 79

personal data
SURNAME	Gram, Jørgen Pedersen
BRIEF DESCRIPTION	Danish mathematician
DATE OF BIRTH	June 27, 1850
PLACE OF BIRTH	Nustrup at Haderslev
DATE OF DEATH	April 29, 1916
Place of death	Copenhagen

[1] Gram: Sur les zeros de la fonction de Riemann ${\ displaystyle \ zeta (s)}$ , Acta Mathematica, Volume 27, 1903, pp. 289-304

[2] Gram's Law in Eric Weissteins MathWorld

[3] E. Karkoschka, P. Werner: Some exceptions to Rosser's rule in the theory of the Riemann zeta function , Computing 27 (1981), pp. 57-69

[4] Henri Cohen : A course in computational algebraic number theory , Springer 1993, p. 79