László Babai | |
|---|---|
 Babai atOberwolfach in 2011 | |
| Born | (1950-07-20)July 20, 1950 (age 75) Budapest, Hungary |
| Citizenship |
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| Alma mater | Hungarian Academy of Sciences |
| Awards | Gödel Prize (1993) Knuth Prize (2015) Dijkstra Prize (2016) |
| Scientific career | |
| Fields | Computer Science, Mathematics |
| Institutions | University of Chicago |
| Doctoral advisor | Pál Turán Vera T. Sós |
| Doctoral students | Mario Szegedy Gábor Tardos Péter Pál Pálfy Barry Guiduli |
László "Laci" Babai (born July 20, 1950, inBudapest)[1] is a Hungarian-American professor of computer science and mathematics at theUniversity of Chicago. His research focuses oncomputational complexity theory,algorithms,combinatorics, andfinite groups, with an emphasis on the interactions between these fields.
In 1968, Babai won a gold medal at theInternational Mathematical Olympiad. Babai studied mathematics atFaculty of Science of theEötvös Loránd University from 1968 to 1973, received a PhD from theHungarian Academy of Sciences in 1975, and received a DSc from the Hungarian Academy of Sciences in 1984.[1][2] He held a teaching position at Eötvös Loránd University since 1971; in 1987 he took joint positions as a professor inalgebra at Eötvös Loránd and in computer science at the University of Chicago. In 1995, he began a joint appointment in the mathematics department at Chicago and gave up his position at Eötvös Loránd.[1]
He is the author of over 180 academic papers.[1]His notable accomplishments include the introduction ofinteractive proof systems,[3] the introduction of the termLas Vegas algorithm,[4] and the introduction ofgroup theoretic methods ingraph isomorphism testing.[4] In November 2015, he announced aquasipolynomial time algorithm for thegraph isomorphism problem.[5][6]
He is editor-in-chief of the refereed online journalTheory of Computing.[7] Babai was also involved in the creation of theBudapest Semesters in Mathematics program and first coined the name.
After announcing the result in 2015,[6][8][9]Babai presented a paper proving that thegraph isomorphism problem can be solved inquasi-polynomial time in 2016, at the ACMSymposium on Theory of Computing.[10] In response to an error discovered byHarald Helfgott, he posted an update in 2017.[11]
We show that theGraph Isomorphism (GI) problem and the related problems of String Isomorphism[12] (under group action) (SI) and Coset Intersection (CI)[13][14] can be solved in quasipolynomial time. The best previous bound for GI was where is the number of vertices (Luks, 1983); for the other two problems, the bound was similar, where is the size of the permutation domain (Babai, 1983).
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.
In 1988, Babai won the Hungarian State Prize, in 1990 he was elected as a corresponding member of the Hungarian Academy of Sciences, and in 1994 he became a full member.[1] In 1999 theBudapest University of Technology and Economics awarded him an honorary doctorate.[1]
In 1993, Babai was awarded theGödel Prize together withShafi Goldwasser,Silvio Micali,Shlomo Moran, andCharles Rackoff, for their papers on interactive proof systems.[15]
In 2005, he received theQuantrell Award.[16]
In 2015, he was elected[17] a fellow of theAmerican Academy of Arts and Sciences, and won theKnuth Prize.
Babai was an invited speaker at theInternational Congresses of Mathematicians inKyoto (1990),Zürich (1994, plenary talk), andRio de Janeiro (2018).
