God made the integers; all else is the work of man.

In analysis Kronecker rejected the formulation of a continuous nowhere differentiable function by his colleague Karl Weierstrass. 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. Kronecker studied elliptic functions and conjectured his "liebster Jugendtraum" ("dearest dream of youth") a generalization that was later put forward by Hilbert in a modified form as his twelfth problem.

He criticized Cantor's work on set theory and was quoted by Weber (1893) as having said "God made natural numbers; all else is the work of man". Kronecker was a student and lifelong friend of Ernst Kummer. Leopold Kronecker (December 7 1823 – December 29 1891) was a German mathematician who worked on number theory and algebra.