What is Karl Weierstraß?
{{Infobox scientist | name = Karl Weierstrass | native_name = Karl Weierstraß | image = Karl Weierstrass 2.jpg | caption = painting by Conrad Fehr , 1895 | birth_date = {{birth date|1815|10|31|df=y}} | birth_place = [[Kingdom of Prussia]] | death_date = {{death date and age|1897|2|19|1815|10|31|df=y}} | death_place = [[Berlin]], [[Kingdom of Prussia]] | nationality = [[Germans|German]] | field = Mathematics | work_institution = [[Technical University of Berlin|Gewerbeinstitut]] | alma_mater = [[University of Bonn]] | doctoral_students = {{unbulleted list|item_style=margin:0 |[[Georg Cantor]] |[[Sofya Kovalevskaya]]}} | known_for = {{unbulleted list|item_style=margin:0 |Weierstrass product inequality |(ε, δ)-definition of limit |Weierstrass–Erdmann condition |Bolzano–Weierstrass theorem}} | prizes = {{unbulleted list |[[Copley Medal]] (1895)}} | footnotes = }} '''Karl Theodor Wilhelm Weierstraß''' (31 October 1815 - 19 February 1897) was a [[Germany|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 function]]s, [[differential geometry]] and the [[calculus of variations]]. The [[Bolzano–Weierstrass theorem|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. {{bio-stub}} {{authority control}} {{DEFAULTSORT:Weierstrass, Karl}} [[Category:1815 births]] [[Category:1897 deaths]] [[Category:German mathematicians]]