Elekes started his mathematical work in combinatorial set theory, answering some questions posed by Erdős and Hajnal. One of his results states that if the set of infinite subsets of the set of natural numbers is split into countably many parts, then in one of them, there is a solution of the equation A∪B=C.[1][6] His interest later switched to another favorite topic of Erdős, discrete geometry and geometric algorithm theory. In 1986 he proved that if a deterministic polynomial algorithm computes a number V(K) for every convex body K in any Euclidean space given by a separation oracle such that V(K) always at least vol(K), the volume of K, then for every large enough dimension n, there is a convex body in the n-dimensional Euclidean space such that V(K)>20.99nvol(K). That is, any polynomial-time estimator of volume over K must be inaccurate by at least an exponential factor.[1][4]
^Elekes, György; Erdős, Paul; Hajnal, András (1978). "On some partition properties of families of sets". Studia Scientiarum Mathematicarum Hungarica: 151–155.
^On lattices, distinct distances, and the Elekes-Sharir framework,
Javier Cilleruelo, Micha Sharir, Adam Sheffer, https://arxiv.org/abs/1306.0242