ECCC-Report TR19-181https://eccc.weizmann.ac.il/report/2019/181Comments and Revisions published for TR19-181en-usTue, 18 Feb 2020 12:39:47 +0200
Revision 1
| A Separator Theorem for Hypergraphs and a CSP-SAT Algorithm |
Navid Talebanfard,
Michal Koucky,
Vojtech Rodl
https://eccc.weizmann.ac.il/report/2019/181#revision1We show that for every $r \ge 2$ there exists $\epsilon_r > 0$ such that any $r$-uniform hypergraph on $m$ edges with bounded vertex degree has a set of at most $(\frac{1}{2} - \epsilon_r)m$ edges the removal of which breaks the hypergraph into connected components with at most $m/2$ edges. We use this to give an algorithm running in time $d^{(1 - \epsilon_r)m}$ that decides satisfiability of $m$-variable $(d, k)$-CSPs in which every variable appears in at most $r$ constraints, where $\epsilon_r$ depends only on $r$ and $k\in o(\sqrt{m})$. We will also show that CNF representations of unsatisfiable $(2, k)$-CSPs with variable frequency $r$ can be refuted in tree-like resolution in size $2^{(1 - \epsilon_r)m}$. Furthermore for Tseitin formulas on graphs with degree at most $k$ (which are $(2, k)$-CSPs) we give a deterministic algorithm finding such a refutation.Tue, 18 Feb 2020 12:39:47 +0200https://eccc.weizmann.ac.il/report/2019/181#revision1
Paper TR19-181
| A Separator Theorem for Hypergraphs and a CSP-SAT Algorithm |
Navid Talebanfard,
Michal Koucky,
Vojtech Rodl
https://eccc.weizmann.ac.il/report/2019/181We show that for every $r \ge 2$ there exists $\epsilon_r > 0$ such that any $r$-uniform hypergraph on $m$ edges with bounded vertex degree has a set of at most $(\frac{1}{2} - \epsilon_r)m$ edges the removal of which breaks the hypergraph into connected components with at most $m/2$ edges. We use this to give a satisfiability algorithm for $n$-variable $(d, k)$-CSPs in which every variable appears in at most $r$ constraints in time $d^{(1 - \epsilon_r)n}$ where $\epsilon_r$ depends only on $r$, provided that $k$ is small enough as a function of $m$. We will also show that unsatisfiable $(2, k)$-CSPs with variable frequency $r$ can be refuted in tree-like resolution in size $2^{(1 - \epsilon_r)n}$. Furthermore for Tseitin formulas on graphs with degree at most $k$ (which are $(2, k)$-CSPs) we give a deterministic algorithm finding such a refutation.Fri, 13 Dec 2019 16:39:31 +0200https://eccc.weizmann.ac.il/report/2019/181