Karl Weierstraß

Karl Weierstrass
Karl Weierstrass
Karl Weierstraß
	painting by Conrad Fehr , 1895
Born	31 October 1815; Kingdom of Prussia
Died	19 February 1897 (aged 81); Berlin, Kingdom of Prussia
Nationality	German
Alma mater	University of Bonn
Known for	Weierstrass product inequality; (ε, δ)-definition of limit; Weierstrass–Erdmann condition; Bolzano–Weierstrass theorem;
Awards	Copley Medal (1895);
	Scientific career
Fields	Mathematics
Institutions	Gewerbeinstitut
Doctoral students	Georg Cantor; Sofya Kovalevskaya;

Karl Theodor Wilhelm Weierstraß (31 October 1815 - 19 February 1897) was a German mathematician. Most of his work is about using logic as a thorough foundation of analysis. He mainly used power series for this. He also provided foundations for the theory of elliptic functions, differential geometry and the calculus of variations. The Bolzano-Weierstrass theorem is named in his honour: according to the theorem, every bounded sequence of real numbers has at least one limit point. He criticised earlier mathematicians for using assumptions too often, and being too vague in their definitions.