Title: A Faster Combinatorial Algorithm for Maximum Bipartite Matching
| Speaker: | Sanjeev Khanna |
| Affiliation: | University of Pennsylvania |
| Location: | MC 5501 |
Abstract: The maximum bipartite matching problem is among the most fundamental and well-studied problems in combinatorial optimization. A beautiful and celebrated combinatorial algorithm of Hopcroft and Karp (1973) shows that maximum bipartite matching can be solved in $O(m \sqrt{n})$ time on a graph with $n$ vertices and $m$ edges. For the case of very dense graphs, a fast matrix multiplication based approach gives a running time of $O(n^{2.371})$. These results represented the fastest known algorithms for the problem until 2013, when Madry introduced a new approach based on continuous techniques achieving much faster runtime in sparse graphs. This line of research has culminated in a spectacular recent breakthrough due to Chen et al. (2022) that gives an $m^{1+o(1)}$ time algorithm for maximum bipartite matching (and more generally, for min cost flows).
This raises a natural question: are continuous techniques essential to obtaining fast algorithms for the bipartite matching problem? In this talk, we will present a new, purely combinatorial algorithm for bipartite matching, that runs in $\tilde{O}(m^{1/3}n^{5/3})$ time, and hence outperforms both Hopcroft-Karp and the fast matrix multiplication based algorithms on moderately dense graphs.
This is joint work with Julia Chuzhoy (TTIC).