Biography
Leopold Kronecker was born on 7 December 1823 in
Liegnitz,
Prussia (now Legnica,
Poland) in a wealthy
Jewish family. His parents, Isidor and Johanna (née Prausnitzep), took care of their children's education and provided them with private tutoring at home – Leopold's younger brother
Hugo Kronecker would also follow a scientific path, later becoming a notable
physiologist. Kronecker then went to the Liegnitz
Gymnasium where he was interested in a wide range of topics including science, history and philosophy, while also practicing gymnastics and swimming. At the gymnasium he was taught by
Ernst Kummer, who noticed and encouraged the boy's interest in mathematics.^{
[2]}
In 1841 Kronecker became a student at the
University of Berlin where his interest did not immediately focus on mathematics, but rather spread over several subjects including astronomy and philosophy. He spent the summer of 1843 at the
University of Bonn studying astronomy and 1843–44 at the
University of Breslau following his former teacher Kummer. Back in Berlin, Kronecker studied mathematics with
Peter Gustav Lejeune Dirichlet and in 1845 defended his dissertation in
algebraic number theory written under Dirichlet's supervision.^{
[3]}
After obtaining his degree, Kronecker did not follow his interest in research on an academic career path. He went back to his hometown to manage a large farming estate built up by his mother's uncle, a former banker. In 1848 he married his cousin Fanny Prausnitzer, and the couple had six children. For several years Kronecker focused on business, and although he continued to study mathematics as a hobby and corresponded with Kummer, he published no mathematical results.^{
[4]} In 1853 he wrote a memoir on the algebraic solvability of equations extending the work of
Évariste Galois on the
theory of equations.
Grave of Kronecker (St Matthäus, Berlin)
Due to his business activity, Kronecker was financially comfortable, and thus he could return to Berlin in 1855 to pursue mathematics as a private scholar. Dirichlet, whose wife
Rebecka came from the wealthy
Mendelssohn family, had introduced Kronecker to the Berlin elite. He became a close friend of
Karl Weierstrass, who had recently joined the university, and his former teacher Kummer who had just taken over Dirichlet's mathematics chair.^{
[2]} Over the following years Kronecker published numerous papers resulting from his previous years' independent research. As a result of this published research, he was elected a member of the
Berlin Academy in 1861.
Although he held no official university position, Kronecker had the right as a member of the Academy to hold classes at the University of Berlin and he decided to do so, starting in 1862. In 1866, when
Riemann died, Kronecker was offered the mathematics chair at the
University of Göttingen (previously held by
Carl Gauss and Dirichlet), but he refused, preferring to keep his position at the Academy. Only in 1883, when Kummer retired from the University, was Kronecker invited to succeed him and became an ordinary professor.^{
[5]} Kronecker was the supervisor of
Kurt Hensel,
Adolf Kneser,
Mathias Lerch, and
Franz Mertens, amongst others.
His philosophical view of mathematics put him in conflict with several mathematicians over the years, notably straining his relationship with Weierstrass, who almost decided to leave the University in 1888.^{
[3]} Kronecker died on 29 December 1891 in Berlin, several months after the death of his wife. In the last year of his life, he converted to
Christianity.^{
[2]} He is buried in the
Alter St Matthäus Kirchhof cemetery in
Berlin-
Schöneberg, close to
Gustav Kirchhoff.