Georg Cantor

Georg Ferdinand Ludwig Philipp Cantor (1845-1918) was a German mathematician best known as the inventor of set theory, which has become a fundamental theory in mathematics. Cantor established the importance of one-to-one correspondence between sets, defined infinite and well-ordered sets, and proved that the real numbers are "more numerous" than the natural numbers. In fact, Cantor's theorem implies the existence of an "infinity of infinities."

Cantor was one if his parents six children. His father wanted him to become an engineer. Georg was not at all happy about this idea. After several years of training, he became so fed up with the idea that he asked his father's permission to become a mathematician. Just before entering college, his father let Georg study mathematics. Cantor, said he would not "displease him."

In 1867 at age 22 he received his PhD in mathematics from Berlin University, writing his thesis on number theory. He took a position at the University of Halle; but, his hopes were on something more prestigious. Despite being promoted to extraordinary professor in 1872 and full Professor in 1879, the wider mathematical community did not accept his ideas, notably those on infinities. Henri Poincare expressed his disapproval, stating that Cantor's set theory would be considered by future generations as "a disease from which one has recovered," and onetime mentor Leopold Kronecker described Cantor as "a corruptor of youth."

Cantor had seems to have suffered from depression and these blows from well known mathematicians may have exacerbated his condition. In 1884 at the age of 39 he suffered a breakdown and was hospitalized. He was to in such conditions several times in his working life. Despite having In 1904, being awarded a medal by the Royal Society of London and being made a member of both the London Mathematical Society and the Society of Sciences in Gottingen in 1904, Georg Cantor died in a mental institution on January 6, 1918.