{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T11:10:59Z","timestamp":1760440259357},"reference-count":4,"publisher":"World Scientific Pub Co Pte Lt","issue":"01","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Comput. Geom. Appl."],"published-print":{"date-parts":[[1998,2]]},"abstract":"<jats:p> A pair of points s and g on the boundary of a simple polygon P admits a walk if two guards can simultaneously walk along the two boundary chains of P from s to g such that they are always visible to each other. The walk is a counter-walk if one guard moves from s to g while the other moves from g to s in the same direction along the boundary and they are always visible to each other. The (counter-)walk is straight if no backtracking is necessary during the (counter-)walk. In this paper, we show that, given a polygon with n vertices, to test if there exists (s,g) that admits a (straight) (counter-)walk can be solved in time O(n log n) and in linear space. Also we compute all (s,g)'s that admit a (straight) walk in O(n log n) time and all vertex pairs that admit a (straight) counter-walk in O(n log n + m), where m is O(n<jats:sup>2<\/jats:sup>). <\/jats:p>","DOI":"10.1142\/s0218195998000060","type":"journal-article","created":{"date-parts":[[2003,7,22]],"date-time":"2003-07-22T11:10:21Z","timestamp":1058872221000},"page":"85-116","source":"Crossref","is-referenced-by-count":37,"title":["Two-Guard Walkability of Simple Polygons"],"prefix":"10.1142","volume":"08","author":[{"given":"L. H.","family":"Tseng","sequence":"first","affiliation":[{"name":"Department of Applied Mathematics, Feng Chia University, Taichung 407, Taiwan, ROC"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"P.","family":"Heffernan","sequence":"additional","affiliation":[{"name":"The Prudential Insurance Company of America, 213 Washington St., Newark, NJ 07102-2992, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D. T.","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL 60208, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"219","published-online":{"date-parts":[[2011,11,20]]},"reference":[{"key":"p_3","doi-asserted-by":"publisher","DOI":"10.1007\/BF01840360"},{"key":"p_5","doi-asserted-by":"publisher","DOI":"10.1007\/BF01553883"},{"key":"p_6","first-page":"3","volume":"2","author":"Icking C.","year":"1992","journal-title":"Int'l J. Comput. Geometry & Application"},{"key":"p_8","doi-asserted-by":"publisher","DOI":"10.1137\/0219071"}],"container-title":["International Journal of Computational Geometry &amp; Applications"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.worldscientific.com\/doi\/pdf\/10.1142\/S0218195998000060","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,8,7]],"date-time":"2019-08-07T00:31:45Z","timestamp":1565137905000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.worldscientific.com\/doi\/abs\/10.1142\/S0218195998000060"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1998,2]]},"references-count":4,"journal-issue":{"issue":"01","published-online":{"date-parts":[[2011,11,20]]},"published-print":{"date-parts":[[1998,2]]}},"alternative-id":["10.1142\/S0218195998000060"],"URL":"https:\/\/doi.org\/10.1142\/s0218195998000060","relation":{},"ISSN":["0218-1959","1793-6357"],"issn-type":[{"value":"0218-1959","type":"print"},{"value":"1793-6357","type":"electronic"}],"subject":[],"published":{"date-parts":[[1998,2]]}}}