Career
He is on the advisory board of the journal Combinatorica. He is best known for his work in extremal graph theory. Among other things, he discovered the method of progressive induction which he used to describe graphs which do not contain a predetermined graph and the number of edges is close to maximal.
With Lovász, he gave a randomized algorithm using O(n7 log2 n) separation calls to approximate the volume of a convex body within a fixed relative error.
Simonovits was also one of the most frequent collaborators with Paul Erdős, co-authoring 21 papers with him.