{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T05:04:07Z","timestamp":1767675847184,"version":"build-2065373602"},"reference-count":6,"publisher":"Elsevier BV","issue":"5","license":[{"start":{"date-parts":[[2003,7,1]],"date-time":"2003-07-01T00:00:00Z","timestamp":1057017600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2003,7,1]],"date-time":"2003-07-01T00:00:00Z","timestamp":1057017600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/legal\/tdmrep-license"},{"start":{"date-parts":[[2013,7,17]],"date-time":"2013-07-17T00:00:00Z","timestamp":1374019200000},"content-version":"vor","delay-in-days":3669,"URL":"http:\/\/www.elsevier.com\/open-access\/userlicense\/1.0\/"}],"content-domain":{"domain":["elsevier.com","sciencedirect.com"],"crossmark-restriction":true},"short-container-title":["Applied Mathematics Letters"],"published-print":{"date-parts":[[2003,7]]},"DOI":"10.1016\/s0893-9659(03)00073-9","type":"journal-article","created":{"date-parts":[[2003,9,11]],"date-time":"2003-09-11T17:05:40Z","timestamp":1063299940000},"page":"723-727","update-policy":"https:\/\/doi.org\/10.1016\/elsevier_cm_policy","source":"Crossref","is-referenced-by-count":3,"title":["The post correspondence problem over a unary alphabet"],"prefix":"10.1016","volume":"16","author":[{"given":"P","family":"Rudnicki","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"G.J","family":"Woeginger","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"78","reference":[{"key":"10.1016\/S0893-9659(03)00073-9_BIB1","doi-asserted-by":"crossref","first-page":"264","DOI":"10.1090\/S0002-9904-1946-08555-9","article-title":"A variant of a recursively unsolvable problem","volume":"52","author":"Post","year":"1946","journal-title":"Bulletin of the American Mathematical Society"},{"key":"10.1016\/S0893-9659(03)00073-9_BIB2","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1016\/0304-3975(89)90080-7","article-title":"The (generalized) Post correspondence problem with lists consisting of two words is decidable","volume":"21","author":"Ehrenfeucht","year":"1982","journal-title":"Theoretical Computer Science"},{"key":"10.1016\/S0893-9659(03)00073-9_BIB3","series-title":"Proceedings of the 11th Annual IEEE Symposium on Logic in Computer Science (LICS'1996)","first-page":"523","article-title":"Decision problems for semi-Thue systems with a few rules","author":"Matiyasevich","year":"1996"},{"year":"1979","series-title":"Computers and Intractability: A Guide to the Theory of NP-Completeness","author":"Garey","key":"10.1016\/S0893-9659(03)00073-9_BIB4"},{"key":"10.1016\/S0893-9659(03)00073-9_BIB5","series-title":"Proceedings of the 2nd International Conference on Computers and Games (CG'2000)","first-page":"214","article-title":"Creating difficult instances of the Post correspondence problem","author":"Lorentz","year":"2000"},{"article-title":"Solving and creating difficult instances of Post's correspondence problem","year":"2002","author":"Zhao","key":"10.1016\/S0893-9659(03)00073-9_BIB6"}],"container-title":["Applied Mathematics Letters"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0893965903000739?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0893965903000739?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:07:51Z","timestamp":1760238471000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0893965903000739"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2003,7]]},"references-count":6,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2003,7]]}},"alternative-id":["S0893965903000739"],"URL":"https:\/\/doi.org\/10.1016\/s0893-9659(03)00073-9","relation":{},"ISSN":["0893-9659"],"issn-type":[{"type":"print","value":"0893-9659"}],"subject":[],"published":{"date-parts":[[2003,7]]},"assertion":[{"value":"Elsevier","name":"publisher","label":"This article is maintained by"},{"value":"The post correspondence problem over a unary alphabet","name":"articletitle","label":"Article Title"},{"value":"Applied Mathematics Letters","name":"journaltitle","label":"Journal Title"},{"value":"https:\/\/doi.org\/10.1016\/S0893-9659(03)00073-9","name":"articlelink","label":"CrossRef DOI link to publisher maintained version"},{"value":"converted-article","name":"content_type","label":"Content Type"},{"value":"Copyright \u00a9 2003 Published by Elsevier Ltd.","name":"copyright","label":"Copyright"}]}}