Carl Gustav Axel Harnack was a Baltic German mathematician who contributed to potential theory. Harnack's inequality applied to harmonic functions. He also worked on the real algebraic geometry of plane curves, proving Harnack's curve theorem for real plane algebraic curves.
- Occupation
- mathematician, university teacher
- Citizenship
- Russian Empire
- Born
- May 7, 1851
- Died
- April 3, 1888
