In November 2015, László Babai, a mathematician and computer scientist at the University of Chicago, claimed to have proven that the graph isomorphism problem is solvable in quasi-polynomial time. He published preliminary versions of these results in the proceedings of the 2016 Symposium on Theory of Computing, and of the 2018 International Congress of Mathematicians. In January 2017, Babai briefly retracted the quasi-polynomiality claim and stated a sub-exponential time time complexity bound instead. He restored the original claim five days later. , the full journal version of Babai's paper has not yet been published.