Vera T. Sós

Vera Turán Sós (11 September 1930 – 22 March 2023)[1][2] was a Hungarian mathematician who specialized in number theory and combinatorics.

She also collaborated frequently with her husband Pál Turán, an analyst, number theorist, and combinatorist.

One of her contributions is the Kővári–Sós–Turán theorem concerning the maximum possible number of edges in a bipartite graph that does not contain certain complete subgraphs.

Another is the following so-called friendship theorem proved with Paul Erdős and Alfréd Rényi: if, in a finite graph, any two vertices have exactly one common neighbor, then some vertex is joined to all others.

As an adolescent, Sós attended the Abonyi Street Jewish high school in Budapest and graduated in 1948.

In 1965, Sós began the weekly Hajnal–Sós seminar at the Mathematical Institute of the Hungarian Academy for Science with András Hajnal.