We study the maximum matching problem in the random-order semi-streaming setting. In this problem, the edges of an arbitrary $n$-vertex graph $G=(V, E)$ arrive in a stream one by one and in a random order. The goal is to have a single pass over the stream, use $n cdot poly(log n)$ space, and output a large matching of $G$. We prove that for an absolute constant $epsilon_0 > 0$, one can find a $(2/3 + epsilon_0)$-approximate maximum matching of $G$ using $O(n log n)$ space with high probability. This breaks the natural boundary of $2/3$ for this problem prevalent in the prior work and resolves an open problem of Bernstein [ICALP20] on whether a $(2/3 + Omega(1))$-approximation is achievable.
تحميل البحث