no code implementations • 2 Dec 2020 • Vadim Lozin, Igor Razgon
We prove that the tree-width of graphs in a hereditary class defined by a finite set $F$ of forbidden induced subgraphs is bounded if and only if $F$ includes a complete graph, a complete bipartite graph, a tripod (a forest in which every connected component has at most 3 leaves) and the line graph of a tripod.
Combinatorics Discrete Mathematics
no code implementations • 25 Aug 2017 • Andrea Calì, Florent Capelli, Igor Razgon
We give a non-FPT lower bound on the size of structured decision DNNF and OBDD with decomposable AND-nodes representing CNF-formulas of bounded incidence treewidth.
no code implementations • 10 Oct 2015 • Igor Razgon
In this paper we study complexity of an extension of ordered binary decision diagrams (OBDDs) called $c$-OBDDs on CNFs of bounded (primal graph) treewidth.
no code implementations • 2 Nov 2014 • Igor Razgon
In this paper we prove a space lower bound of $n^{\Omega(k)}$ for non-deterministic (syntactic) read-once branching programs ({\sc nrobp}s) on functions expressible as {\sc cnf}s with treewidth at most $k$ of their primal graphs.
no code implementations • 16 Jan 2014 • Emmanuel Hebrard, Dániel Marx, Barry O'Sullivan, Igor Razgon
Moreover, we show that the maximum number of pairs of equal variables can be approximated by a factor 1/2 with a linear time greedy algorithm.