Georg Cantor

Danish-German mathematician Georg Ferdinand Ludwig Philipp Cantor (1845-1918) introduced set theory and the concept of transfinite numbers.

Cantor's doctoral thesis was titled "In mathematics the art of asking questions is more valuable than solving problems." He became a professor at the University of Halle; his later attempt to join the faculty of the University of Berlin was blocked by his former teacher, Leopold Kronecker, who disagreed with Cantor's innovative theories.