Poul Heegaard

Poul Heegaard, ca.1940

Poul Heegaard (born November 2, 1871 in Copenhagen , † February 7, 1948 in Oslo ) was a Danish mathematician who dealt with topology .

Life

Heegaard studied from 1889 to 1893 at the University of Copenhagen with Hieronymus Zeuthen . After graduating in 1893, he visited Paris . However, according to his own autobiographical notes (discovered in 1997), the visit was a failure (he did not meet Henri Poincaré either ). Then he went to the University of Göttingen , where the time with Felix Klein was very stimulating for him. He studied four-dimensional manifolds and their topology in an effort to better understand algebraic functions in two variables and, for the sake of simplicity, started with three-dimensional manifolds, which was to become his main field of work.

In his dissertation from 1898 he introduced Heegaard decompositions and diagrams into the topology of three-dimensional manifolds. Heegaard demonstrated the possibility of breaking down closed 3-manifolds into "handle bodies", whereby the way in which these handle bodies are attached to form 3-manifolds is noted in the Heegaard diagrams. He also gave a counterexample to Henri Poincaré's version of the Poincaré duality at the time, who then had to change his concept. After receiving his doctorate, he was a teacher at the naval cadet school until 1910.

In 1907 he published the important review article Analysis Situs in the Encyclopedia of Mathematical Sciences with Max Dehn . This is the foundation of the combinatorial topology, which made it possible for them to provide the first strict proof of the classification of compact surfaces by gender.

In 1910 he became a professor at the University of Copenhagen, but resigned in 1918. The reason he gave was work overload and disagreements with colleagues. He then became a professor at the University of Oslo in 1918 , where he retired in 1941. He was a co-founder of the Norwegian Mathematical Society and co-editor of the works of Sophus Lie .

Fonts

• Dehn, Heegaard Analysis Situs , Encyclopedia of Mathematical Sciences 1907

Web links

• Page with the biography of Munkholm, part of his dissertation and Heegard's autobiographical notes
• John J. O'Connor, Edmund F. Robertson :  Poul Heegaard. In: MacTutor History of Mathematics archive .
• Literature by and about Poul Heegaard in the SUDOC catalog (Association of French University Libraries)