Carl Gustav Axel Harnack

Carl Gustav Axel Harnack (born 25 Apriljul / 7 May 1851greg in Dorpat, .. † April 3, 1888 in Dresden ) was a German mathematician who worked on real algebraic geometry, analysis and mathematical physics.

Life and work

Harnack, son of Theodosius Harnack theology professor, studied from 1869 in Dorpat and from 1874 in Erlangen, where he earned his doctorate under Felix Klein. In the winter semester 1875/6, he habilitated in Leipzig, where he was a lecturer afterwards. From 1876 he was a professor at the Technical University of Darmstadt and in 1877 at the Technical University Dresden.

Harnack was a pioneer in the real algebraic geometry, where the set of Harnack (1876 ) states that a real algebraic curve of order n in the projective plane is divided into a maximum of parts.

In the potential theory, he is known for Harnack 's inequalities for harmonic functions. He is also one of the pioneers in the introduction of the Maßbegriffs in the Analysis (next to Georg Cantor and Otto Stolz ).

Axel Harnack was the twin brother of the theologian Adolf (from) Harnack; a younger brother was the pharmacologist Erich Harnack, another younger brother, the literary scholar Otto Harnack. He died in 1888 in Dresden and was buried in the Trinity Cemetery.

Writings

• The elements of the differential and integral calculus. As an introduction to the study. B. G. Teubner, Leipzig, 1881. Internet Archive
• The foundations of the theory of the logarithmic Potentiales and the unique potential function in the plane. B. G. Teubner, Leipzig, 1887. Internet Archive
• Leibniz's importance in the history of mathematics. v. Zahn & Jaensch, Dresden 1887. Internet Archive