{"type":"ScholarlyArticle","title":"A New Variable Ordering for In-processing Bounded Variable Elimination in SAT Solvers","authors":[{"name":"Shuolin Li","slug":"shuolin-li","given":"Shuolin","family":"Li","affiliation":"Aix Marseille Univ , Université de Toulon , CNRS , LIS , Marseille , France"},{"name":"Chu-Min Li","slug":"chu-min-li","given":"Chu-Min","family":"Li","affiliation":"Aix Marseille Univ , Université de Toulon , CNRS , LIS , Marseille , France; Université de Picardie Jules Verne , Amiens , France"},{"name":"Mao Luo","slug":"mao-luo","given":"Mao","family":"Luo","affiliation":"Hubei University of Technology , Wuhan , China"},{"name":"Jordi Coll","slug":"jordi-coll","given":"Jordi","family":"Coll","affiliation":"Artificial Intelligence Research Institute , CSIC , Bellaterra , Spain"},{"name":"Djamal Habet","slug":"djamal-habet","given":"Djamal","family":"Habet","affiliation":"Aix Marseille Univ , Université de Toulon , CNRS , LIS , Marseille , France"},{"name":"Felip Manyà","slug":"felip-manya","given":"Felip","family":"Manyà","affiliation":"Artificial Intelligence Research Institute , CSIC , Bellaterra , Spain"}],"abstract":"Bounded Variable Elimination (BVE) is an important Boolean formula simplification technique in which the variable ordering is crucial. We define a new variable ordering based on variable activity, called ESA (variable Elimination Scheduled by Activity), for in-processing BVE in Conflict-Driven Clause Learning (CDCL) SAT solvers, and incorporate it into several state-of-the-art CDCL SAT solvers. Experimental results show that the new ESA ordering consistently makes these solvers solve more instances on the benchmark set including all the 5675 instances used in the Crafted, Application and Main tracks of all SAT Competitions up to 2022. In particular, one of these solvers with ESA, Kissat_MAB_ESA, won the Anniversary track of the SAT Competition 2022.  The behaviour of ESA and the reason of its effectiveness are also analyzed.","doi":"10.24963/ijcai.2023/220","url":"https://ijcai.org/proceedings/2023/220","pdf":"https://ijcai.org/proceedings/2023/0220.pdf","markdown":"https://ijcai.org/proceedings/2023/220.md","bibtex":"https://ijcai.org/proceedings/2023/bibtex/220","volume":{"slug":"2023","title":"Proceedings of the Thirty-Second International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2023","url":"https://ijcai.org/proceedings/2023/","year":2023,"location":"Macao, SAR","dates":"19-25 August 2023","editors":"Edith Elkind","isbn":"978-1-956792-03-4","publisher":"International Joint Conferences on Artificial Intelligence Organization","doi_prefix":"10.24963/ijcai.2023"},"section":"Constraint Satisfaction and Optimization","track":"Main Track","number":220,"pages":{"first":1979,"last":1987},"keywords":["Constraint Satisfaction and Optimization: CSO: Solvers and tools","Constraint Satisfaction and Optimization: CSO: Satisfiabilty"],"videos":[],"references":[{"position":1,"raw":"[Beame et al., 2003] Paul Beame, Henry Kautz, and Ashish Sabharwal. 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