Born: 10 March 1869 in Shavli/ Siaulai, Kovno ( Siaulai, Lithuania)
Died: 8 May 1953 in Moscow, USSR
--------------------------------------------------------------------------------

Benjamin Fedorovich Kagan's father Fedor Kagan was a clerk. Kagan
entered Novorossysky University in Odessa in 1887. He was expelled in
1889 for participating in the Democratic Students Movement. He was
sent to Ekaterinoslav in south-central Ukraine. The Soviets renamed
Ekaterinoslav in 1926 calling it Dnepropetrovsk.

In 1892 Kagan received a degree from Kiev University, then in 1895 he
was awarded a Master's Degree by St Petersburg University.
He taught at Novorossysky from 1897 until 1922, becoming a professor
there in 1917. However this was not his only post during this period
for he taught higher education classes for women and also taught at
the local Jewish school. As if this was not enough, Kagan also edited
the Journal of Experimental Physics and Elementary Mathematics from
1902 until 1917 and he was the director of a large publisher of
scientific materials Mathesis.

In 1922 he went to Moscow when the Department of Differential Geometry
was founded at Moscow State University. Kagan was the first Head of
Department and he founded an important School of Differential
Geometry. He retained his interest in publishing, however, and he was
the director of the science department of a state publisher for ten
years. He also directed the department of mathematics and natural
sciences of the Great Soviet Encyclopaedia.

In 1927, Kagan organised a seminar on vector and tensor analysis. He
founded a publication associated with this seminar Transactions of the
seminar on Vector and Tensor Analysis with its applications to
Geometry, Mechanics and Physics in 1933. In 1934 Kagan and other
members of his School organised an International conference on
differential geometry which took place at Moscow University.

Kagan worked on the foundations of geometry and his first work was on
Lobachevsky's geometry. In 1902 he proposed axioms and definitions
very different from Hilbert. Kagan studied tensor differential
geometry after going to Moscow because of an interest in relativity.

Kagan wrote a history of non-euclidean geometry and also a detailed
biography of Lobachevsky. He edited Lobachevsky's complete works which
appeared in five volumes between 1946 and 1951.

Article by: J J O'Connor and E F Robertson