Walther Mayer (11 March 1887 – 10 September 1948) was an Austrian mathematician, born in Graz, Austria-Hungary. With Leopold Vietoris he is the namesake of the Mayer–Vietoris sequence in topology. He served as an assistant to Albert Einstein, and was nicknamed "Einstein's calculator".
Mayer studied at the Federal Institute of Technology in Zürich and the University of Paris before receiving his doctorate in 1912 from the University of Vienna; his thesis concerned the Fredholm integral equation. He served in the military between 1914 and 1919, during which he found time to complete a habilitation on differential geometry. Because he was Jewish, he had little opportunity for an academic career in Austria, and left the country; however, in 1926, with help from Einstein, he returned to a position at the University of Vienna as Privatdozent (lecturer). He made a name for himself in topology with the Mayer–Vietoris sequence, and with an axiomatic treatment of homology predating the Eilenberg–Steenrod axioms. He also published a book on Riemannian geometry in 1930, the second volume of a textbook on differential geometry that had been started by Adalbert Duschek with a volume on curves and surfaces.
In 1929, on the recommendation of Richard von Mises, he became Albert Einstein's assistant with the explicit understanding that he work with him on distant parallelism, and from 1931 to 1936, he collaborated with Albert Einstein on the theory of relativity. In 1933, after Hitler's assumption of power, he followed Einstein to the United States and became an associate in mathematics at the Institute for Advanced Study in Princeton, New Jersey. He continued working on mathematics at the Institute, and died in Princeton in 1948.
- Pais, Abraham (1982), Subtle is the Lord : The Science and the Life of Albert Einstein: The Science and the Life of Albert Einstein, Oxford University Press, pp. 492–494, ISBN 9780191524028.
- Krömer, Ralph (2007), "2.1.4 The Work of Walther Mayer on Chain Complexes", Tool and Object: A History and Philosophy of Category Theory, Science Networks: Historical Studies, 32, Springer, p. 51, ISBN 9783764375249.
- Topper, David (2012), How Einstein Created Relativity Out of Physics and Astronomy, Astrophysics and Space Science Library, 394, Springer, p. 137, ISBN 9781461447818.
- Walther Mayer at the Mathematics Genealogy Project
- Weibel, Peter (2005), Beyond Art: A Third Culture: A Comparative Study in Cultures, Art and Science in 20th Century Austria and Hungary, Springer, p. 260, ISBN 9783211245620.
- The title of his thesis was Anwendung der Fredholmschen Funktionalgleichung auf einige spezielle Randwertaufgaben des logarithmischen Potentials.
- Havas, Peter (1999), "Einstein, relativity, and gravitation research in Vienna before 1938", in Goenner, Hubert (ed.), The Expanding Worlds of General Relativity, Einstein Studies, 7, Birkhäuser, pp. 161–206, ISBN 9780817640606. See in particular p. 167.
- James, I. M. (1999), History of Topology, Elsevier, p. 120, ISBN 9780080534077.