Heinrich Franz Friedrich Tietze | |
|---|---|
 Heinrich Tietze (right), with Friedrich Hartogs | |
| Born | 31 August 1880 |
| Died | 17 February 1964 (aged 83) |
| Known for | Tietze's graph Tietze extension theorem Tietze transformations Hauptvermutung Lens space |
Heinrich Franz Friedrich Tietze (August 31, 1880 – February 17, 1964) was an Austrian mathematician, famous for the Tietze extension theorem on functions from topological spaces to the real numbers. He also developed the Tietze transformations for group presentations, and was the first to pose the group isomorphism problem. Tietze's graph is also named after him; it describes the boundaries of a subdivision of the Möbius strip into six mutually-adjacent regions, found by Tietze as part of an extension of the four color theorem to non-orientable surfaces.