László "Laci" Babai (born July 20, 1950, in Budapest)[1] is a Hungarian professor of computer science and mathematics at the University of Chicago.

His research focuses on computational complexity theory, algorithms, combinatorics, and finite groups, with an emphasis on the interactions between these fields.

In 1995, he began a joint appointment in the mathematics department at Chicago and gave up his position at Eötvös Loránd.

[4] In November 2015, he announced a quasipolynomial time algorithm for the graph isomorphism problem.

[7] Babai was also involved in the creation of the Budapest Semesters in Mathematics program and first coined the name.

After announcing the result in 2015,[6][8][9] Babai presented a paper proving that the graph isomorphism problem can be solved in quasi-polynomial time in 2016, at the ACM Symposium on Theory of Computing.

The algorithm builds on Luks's SI framework and attacks the barrier configurations for Luks's algorithm by group theoretic «local certificates» and combinatorial canonical partitioning techniques.

We show that in a well-defined sense, Johnson graphs are the only obstructions to effective canonical partitioning.

[1] In 1993, Babai was awarded the Gödel Prize together with Shafi Goldwasser, Silvio Micali, Shlomo Moran, and Charles Rackoff, for their papers on interactive proof systems.

[15] In 2015, he was elected[16] a fellow of the American Academy of Arts and Sciences, and won the Knuth Prize.

Babai was an invited speaker at the International Congresses of Mathematicians in Kyoto (1990), Zürich (1994, plenary talk), and Rio de Janeiro (2018).