A randomized algorithm returns a $(1\pm\varepsilon)-approximation with failure probability at most $\delta$ in $O^*(2^k\varepsilon^{-2}\log(1/\delta)$ time.
Abstract
We resolve the conjecture of Koutis and Williams that $k$-paths can be approximately counted in $O^*(2^k)$ time. For a simple directed graph with $n$ vertices and $m$ arcs, our randomized algorithm returns a $(1\pm\varepsilon)$-approximation with failure probability at most $\delta$ in $O^*(2^k\varepsilon^{-2}\log(1/\delta))$ time.
We show that set cover on a universe of size $n$ and with sets of size at most $k$ can be solved in time $2^{(1-1/k+O(1/k^{3/2}))n}$. This improves on a $2^{(1-0.929/k)n}$-time algorithm of Bj\"orklund (STACS 2010) for all sufficiently large $k$.
We determine, up to a factor of $2^{o(k)}$, the number of $k$-sets $A \subset \{1, \ldots, n\}$ such that $|A + A| \leq m$, where $k = \Theta(\log n)$ and $m \leq k^{1 + \alpha}$, for small $\alpha>0$, answering a question of Green and Morris.
Marcelo Campos, Gabriel Dahia, João Pedro Marciano· 0 citations
Alternative parameterizations of the k-core problem are investigated to identify conditions under which it can be placed into sub-polynomial complexity classes, and the boundary of parallel tractability for the k-core problem is explored.
Let $f(k)$ denote the smallest integer such that every oriented graph $D$ with chromatic number at least $f(k)$ contains every oriented tree on $k$ vertices. Burr (1980) showed that $f(k)\le (k-1)^2$ and conjectured that $f(k)=2k-2$. Bessy, Gon\c{c}alves and Reinald (2025) proved that $f(k)=O(k^{3/2})$. In this paper,...
