{"type":"ScholarlyArticle","title":"Heuristics and Really Hard Instances for Subgraph Isomorphism Problems","authors":[{"name":"Ciaran McCreesh","slug":"ciaran-mccreesh","given":"Ciaran","family":"McCreesh","affiliation":""},{"name":"Patrick Prosser","slug":"patrick-prosser","given":"Patrick","family":"Prosser","affiliation":""},{"name":"James Trimble","slug":"james-trimble","given":"James","family":"Trimble","affiliation":""}],"abstract":"We show how to generate really hard' random instances for subgraph isomorphism problems. For the non-induced variant, we predict and observe a phase transition between satisfiable and unsatisfiable instances, with a corresponding complexity peak seen in three different solvers. For the induced variant, much richer behaviour is observed, and constrainedness gives a better measure of difficulty than does proximity to a phase transition. We also discuss variable and value ordering heuristics, and their relationship to the expected number of solutions.","doi":null,"url":"https://ijcai.org/proceedings/2016/96","pdf":"https://ijcai.org/proceedings/2016/0096.pdf","markdown":"https://ijcai.org/proceedings/2016/96.md","bibtex":"https://ijcai.org/proceedings/2016/bibtex/96","volume":{"slug":"2016","title":"Proceedings of the Twenty-Fifth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2016","url":"https://ijcai.org/proceedings/2016/","year":2016,"location":"New York, NY, USA","dates":"9–15 July 2016","editors":"Subbarao Kambhampati","isbn":"978-1-57735-770-4; 978-1-57735-771-1","publisher":"AAAI Press / International Joint Conferences on Artificial Intelligence","doi_prefix":""},"section":null,"track":"","number":96,"pages":{"first":631,"last":637},"keywords":[],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}