{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T19:20:46Z","timestamp":1779304846310,"version":"3.51.4"},"reference-count":5,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2006,10,4]],"date-time":"2006-10-04T00:00:00Z","timestamp":1159920000000},"content-version":"vor","delay-in-days":7157,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Graph Theory"],"published-print":{"date-parts":[[1987,3]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>For a fixed graph <jats:italic>H<\/jats:italic>, let <jats:italic>H<\/jats:italic>\u2010CON denote the problem of determining whether a given graph is contractible to <jats:italic>H<\/jats:italic>. The complexity of <jats:italic>H<\/jats:italic>\u2010CON is studied for <jats:italic>H<\/jats:italic> belonging to certain classes of graphs, together covering all connected graphs of order at most 4. In particular, <jats:italic>H<\/jats:italic>\u2010CON is NP\u2010complete if <jats:italic>H<\/jats:italic> is a connected triangle\u2010free graph other than a star. For each connected graph <jats:italic>H<\/jats:italic> of order at most 4 other than <jats:italic>P<\/jats:italic><jats:sub>4<\/jats:sub> and <jats:italic>C<\/jats:italic><jats:sub>4<\/jats:sub>, <jats:italic>H<\/jats:italic>\u2010CON is solvable in polynomial time.<\/jats:p>","DOI":"10.1002\/jgt.3190110111","type":"journal-article","created":{"date-parts":[[2007,5,29]],"date-time":"2007-05-29T08:56:36Z","timestamp":1180428996000},"page":"71-79","source":"Crossref","is-referenced-by-count":52,"title":["Contractibility and NP\u2010completeness"],"prefix":"10.1002","volume":"11","author":[{"given":"A. E.","family":"Brouwer","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"H. J.","family":"Veldman","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2006,10,4]]},"reference":[{"key":"e_1_2_1_2_2","doi-asserted-by":"publisher","DOI":"10.1002\/mana.19600220107"},{"key":"e_1_2_1_3_2","volume-title":"Computers and Intractability","author":"Garey M. R.","year":"1979"},{"key":"e_1_2_1_4_2","doi-asserted-by":"publisher","DOI":"10.21236\/AD0705364"},{"key":"e_1_2_1_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/0012-365X(81)90022-4"},{"key":"e_1_2_1_6_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01594196"}],"container-title":["Journal of Graph Theory"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fjgt.3190110111","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/jgt.3190110111","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,21]],"date-time":"2023-10-21T14:36:24Z","timestamp":1697898984000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/jgt.3190110111"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1987,3]]},"references-count":5,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1987,3]]}},"alternative-id":["10.1002\/jgt.3190110111"],"URL":"https:\/\/doi.org\/10.1002\/jgt.3190110111","archive":["Portico"],"relation":{},"ISSN":["0364-9024","1097-0118"],"issn-type":[{"value":"0364-9024","type":"print"},{"value":"1097-0118","type":"electronic"}],"subject":[],"published":{"date-parts":[[1987,3]]}}}