{"id":4085,"date":"2021-06-16T14:48:38","date_gmt":"2021-06-16T18:48:38","guid":{"rendered":"http:\/\/matroidunion.org\/?p=4085"},"modified":"2021-06-21T16:24:35","modified_gmt":"2021-06-21T20:24:35","slug":"online-talk-sebastian-wiederrecht","status":"publish","type":"post","link":"https:\/\/matroidunion.org\/?p=4085","title":{"rendered":"Online Talk: Sebastian Wiederrecht"},"content":{"rendered":"\n<p><strong>Monday, June 21,<\/strong> <strong>3pm ET<\/strong> (8pm BST, 7am Tue NZST)<br \/><strong><a href=\"https:\/\/www.wiederrecht.com\/\">Sebastian Wiederrecht<\/a><\/strong>, LIRMM<br \/><strong>Even Circuits in Oriented Matroids<\/strong><\/p>\n<div><strong>YouTube: <\/strong><a href=\"https:\/\/youtu.be\/rMuRdNFwE5E\">https:\/\/youtu.be\/rMuRdNFwE5E<\/a><\/div>\n<h5>\u00a0<\/h5>\n<h5><b><\/b><strong>Abstract:<\/strong><\/h5>\n<h5>This work generalises the even directed cycle problem, which asks whether a given digraph contains a directed cycle of even length, to orientations of regular matroids. We define non-even oriented matroids generalising non-even digraphs, which played a central role in resolving the computational complexity of the even dicycle problem. Then we show that the problem of detecting an even directed circuit in a regular matroid is polynomially equivalent to the recognition of non-even oriented matroids.<br \/>Our main result is a precise characterisation of the class of non-even oriented bond matroids in terms of forbidden minors, which complements an existing characterisation of non-even oriented graphic matroids by Seymour and Thomassen and reveals an extended class of obstructions.<br \/>This is joint work with Karl Heuer and Raphael Steiner.<\/h5>\n","protected":false},"excerpt":{"rendered":"<p>Monday, June 21, 3pm ET (8pm BST, 7am Tue NZST)Sebastian Wiederrecht, LIRMMEven Circuits in Oriented Matroids YouTube: https:\/\/youtu.be\/rMuRdNFwE5E \u00a0 Abstract: This work generalises the even directed cycle problem, which asks whether a given digraph contains a directed cycle of even &hellip; <a href=\"https:\/\/matroidunion.org\/?p=4085\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":20,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[11],"class_list":["post-4085","post","type-post","status-publish","format-standard","hentry","category-matroids","tag-online-talks"],"_links":{"self":[{"href":"https:\/\/matroidunion.org\/index.php?rest_route=\/wp\/v2\/posts\/4085","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/matroidunion.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/matroidunion.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/matroidunion.org\/index.php?rest_route=\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/matroidunion.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4085"}],"version-history":[{"count":3,"href":"https:\/\/matroidunion.org\/index.php?rest_route=\/wp\/v2\/posts\/4085\/revisions"}],"predecessor-version":[{"id":4092,"href":"https:\/\/matroidunion.org\/index.php?rest_route=\/wp\/v2\/posts\/4085\/revisions\/4092"}],"wp:attachment":[{"href":"https:\/\/matroidunion.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4085"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/matroidunion.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4085"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/matroidunion.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4085"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}