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On Tseitin Formulas, Read-Once Branching Programs and Treewidth
Theory of Computing Systems ( IF 0.5 ) Pub Date : 2020-10-09 , DOI: 10.1007/s00224-020-10007-8
Ludmila Glinskih , Dmitry Itsykson

We show that any nondeterministic read-once branching program that decides a satisfiable Tseitin formula based on an n × n grid graph has size at least 2Ω(n). Then using the Excluded Grid Theorem by Robertson and Seymour we show that for an arbitrary graph G(V, E) any nondeterministic read-once branching program that computes a satisfiable Tseitin formula based on G has size at least \(2^{\Omega (\text {tw}(G)^{\delta })}\) for all δ < 1/36, where tw(G) is the treewidth of G (for planar graphs and some other classes of graphs the statement holds for δ = 1). We apply the mentioned results to the analysis of the complexity of derivations in the proof system OBDD(∧,reordering) and show that any OBDD(∧,reordering)-refutation of an unsatisfiable Tseitin formula based on a graph G has size at least \(2^{\Omega (\text {tw}(G)^{\delta })}\). We also show an upper bound O(|E|2pw(G)) on the size of OBDD representations of a satisfiable Tseitin formula based on G and an upper bound \(O(|E||V| 2^{\text {pw}(G)}+|\text {TS}_{G,c}|^{2})\) on the size of OBDD(∧)-refutation of an unsatisifable Tseitin formula TSG, c, where pw(G) is the pathwidth of G.



中文翻译:

关于Tseitin公式,一次性分支程序和树宽

我们表明,任何基于n × n网格图确定可满足的Tseitin公式的不确定性一次读取分支程序的大小至少为2Ω n。然后使用Robertson和Seymour的排除网格定理,我们表明,对于任意图GVE),任何基于G来计算可满足的Tseitin公式的不确定性一次读取分支程序的大小至少为\(2 ^ {\ Omega (\ {文本TW}(G)^ {\增量})} \)对于所有δ <1/36,其中总重量(g ^)是的树宽ģ(对于平面图和某些其他类型的图,该语句适用于δ = 1)。我们将上述结果应用于证明系统OBDD(∧,reordering)的推导复杂度分析,并表明基于图G的不满足Tseitin公式的任何OBDD(∧,reordering)-反推的大小至少为\ (2 ^ {\ Omega(\ text {tw}(G)^ {\\ delta}}} \)。我们还显示了基于G和可满足的Tseitin公式的OBDD表示的大小的上界O(| E | 2 pw(G)和上界\(O(| E || V | 2 ^ {\ text {pw}(G)} + | \文本{TS} _ {G,c} | ^ {2})\)上OBDD的大小(∧)的unsatisifable Tseitin式TS的-refutation ģÇ,其中PW(ģ)是的pathwidth ģ

更新日期:2020-10-11
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