计算机科学 ›› 2026, Vol. 53 ›› Issue (5): 346-353.doi: 10.11896/jsjkx.250800047

• 人工智能 • 上一篇    下一篇

严格d-正则(3,s)-SAT问题的计算复杂性

王永平1, 符祖峰2   

  1. 1 贵州财经大学信息学院算法与计算复杂性实验室 贵阳 550025
    2 南阳师范学院人工智能与软件工程学院 河南 南阳 473061
  • 收稿日期:2025-08-11 修回日期:2025-11-12 发布日期:2026-05-08
  • 通讯作者: 王永平(wangyp_gc@mail.gufe.edu.cn)
  • 基金资助:
    国家自然科学基金(62362007)

Computational Complexity of Strictly d-regular (3,s)-SAT Problem

WANG Yongping1, FU Zufeng2   

  1. 1 Algorithm and Computational Complexity Laboratory of School of Information, Guizhou University of Finance and Economics, Guiyang 550025, China
    2 School of Artificial Intelligence and Software Engineering, Nanyang Normal University, Nanyang, Henan 473061, China
  • Received:2025-08-11 Revised:2025-11-12 Online:2026-05-08
  • About author:WANG Yongping,born in 1980,Ph.D,associate professor,master’s supervisor.His main research interests include computational complexity and algorithm design and analysis.
  • Supported by:
    National Natural Science Foundation of China(62362007).

摘要: 严格d-正则(3,s)-SAT问题是指:给定一个严格d-正则(3,s)-CNF公式,判定是否存在对其变量的一个真值指派,使公式的真值为真。此处,严格d-正则(3,s)-CNF公式是指:每个子句的长度为3,每个变量的出现次数为s,每个变量的正、负出现次数之差的绝对值为d 的CNF公式。研究表明,一定条件下,严格d-正则(3,s)-SAT问题存在难解实例聚集现象。因此,讨论了严格d-正则(3,s)-SAT问题的计算复杂性,证明了:当 s≥4 时,存在不可满足的严格(s-2)-正则(3,s)-CNF公式和不可满足的严格(s-4)-正则(3,s)-CNF公式。由此,已有的系列结论中的假设条件成为现实。于是,严格d-正则(3,s)-SAT问题的计算复杂性得以解决:当 s≤3 时,严格d-正则(3,s)-CNF公式均可满足;当s≥4d<s时,严格d-正则(3,s)-SAT问题是NP-完全问题;当 s≥4d=s时,严格d-正则(3,s)-CNF公式均可满足。需指出,所得结论意味着,严格0-正则(3,4)-SAT问题和严格2-正则(3,4)-SAT问题均是NP-完全问题,即严格0-正则(3,4)-SAT问题和严格2-正则(3,4)-SAT问题保留了正则(3,4)-SAT问题的NP-完全性,也保留了3-SAT问题的NP-完全性。因此,继续研究严格d-正则(3,s)-SAT问题,尤其是严格0-正则(3,4)-SAT问题和严格2-正则(3,4)-SAT问题应该是必要的。

关键词: 3-SAT问题, 正则(3,s)-SAT问题, 严格d-正则(3,s)-SAT问题, 计算复杂性, NP-完全类

Abstract: he strictly d-regular (3,s)-SAT problem determines whether a given strictly d-regular (3,s)-CNF formula is satisfiable,where a CNF formula is satisfiable if there exists a truth assignment to its variables such that the truth value of the formula is true.A CNF formula is a 3-CNF formula if each clause contains three literals;a 3-CNF formula is a regular (3,s)-CNF formula if each variable appears s times in the formula;and a regular (3,s)-CNF formula is a strictly d-regular (3,s)-CNF formula if the absolute value of the difference between the positive and negative occurrences of each variable is d.Existing research shows that the strictly d-regular (3,s)-SAT problem has an aggregation phenomenon of hard-solving instances under some conditions.Hence,this paper studies the computational complexity of the strictly d-regular (3,s)-SAT problem.It shows that there exists both an unsatisfiable strictly (s-2)-regular (3,s)-CNF formula and an unsatisfiable strictly(s-4)-regular(3,s)-CNF formula when s≥4.Thus,the assumptions underlying the existing series of conclusions are confirmed.Hence,it determines the computational complexity of the strictly d-regular (3,s)-SAT problem as follows.A strictly d-regular (3,s)-CNF formula is satisfiable when s≤3;the strictly d-regular (3,s)-SAT problem is NP-complete when s≥4 and d<s;and a strictly d-regular (3,s)-CNF formula is satisfiable when s≥4 and d=s.It is necessary to say that both the strictly 0-regular (3,4)-SAT problem and the strictly 2-regular (3,4)-SAT problem are NP-complete by the conclusion above.In other words,the strictly 0-regular (3,4)-SAT problem and the strictly 2-regular (3,4)-SAT problem inherit the NP-completeness of both the regular (3,4)-SAT problem and the 3-SAT problem.So,it should be necessary to study further the strictly d-regular (3,s)-SAT problem,especially,to study the strictly 0-regular (3,4)-SAT problem and the strictly 2-regular (3,4)-SAT problem.

Key words: 3-SAT problem, Regular (3, s)-SAT problem, Strictly d-regular (3, s)-SAT problem, Computational complexity, NP-complete class

中图分类号: 

  • TP301.5
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