Many Hard Examples in Exact Phase Transitions with Application to Generating Hard Satisfiable Instances

dc.creatorXu, Ke
dc.creatorLi, Wei
dc.date2003-02-01
dc.date2003-11-11
dc.date.accessioned2026-07-07T03:19:24Z
dc.date.available2026-07-07T03:19:24Z
dc.descriptionThis paper first analyzes the resolution complexity of two random CSP models (i.e. Model RB/RD) for which we can establish the existence of phase transitions and identify the threshold points exactly. By encoding CSPs into CNF formulas, it is proved that almost all instances of Model RB/RD have no tree-like resolution proofs of less than exponential size. Thus, we not only introduce new families of CNF formulas hard for resolution, which is a central task of Proof-Complexity theory, but also propose models with both many hard instances and exact phase transitions. Then, the implications of such models are addressed. It is shown both theoretically and experimentally that an application of Model RB/RD might be in the generation of hard satisfiable instances, which is not only of practical importance but also related to some open problems in cryptography such as generating one-way functions. Subsequently, a further theoretical support for the generation method is shown by establishing exponential lower bounds on the complexity of solving random satisfiable and forced satisfiable instances of RB/RD near the threshold. Finally, conclusions are presented, as well as a detailed comparison of Model RB/RD with the Hamiltonian cycle problem and random 3-SAT, which, respectively, exhibit three different kinds of phase transition behavior in NP-complete problems.
dc.description19 pages, corrected mistakes in Theorems 5 and 6
dc.identifierhttps://arxiv.org/abs/cs/0302001
dc.identifierhttp://arxiv.org/abs/cs/0302001
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/31449
dc.subjectComputational Complexity
dc.subjectStatistical Mechanics
dc.subjectArtificial Intelligence
dc.subjectDiscrete Mathematics
dc.subjectF.2.2; I.2.8
dc.titleMany Hard Examples in Exact Phase Transitions with Application to Generating Hard Satisfiable Instances
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