{"id":968,"date":"2017-12-10T08:41:18","date_gmt":"2017-12-10T06:41:18","guid":{"rendered":"https:\/\/mathematics.haifa.ac.il\/?p=968"},"modified":"2017-12-14T16:42:34","modified_gmt":"2017-12-14T14:42:34","slug":"colloquium-monday-december-11-4-pm-speaker-shira-zerbib-michigan-title-colorful-coverings-of-polytopes-the-hidden-topological-truth-behind-different-colorful-phenomena","status":"publish","type":"post","link":"https:\/\/mathematics.haifa.ac.il\/?p=968","title":{"rendered":"Colloquium: Monday, December 11, 4 pm. Speaker: Shira Zerbib (Michigan). Title: &#8220;Colorful coverings of polytopes &#8211; the hidden topological truth behind different colorful phenomena&#8221;."},"content":{"rendered":"<p>The topological KKMS Theorem is a powerful extension of the Brouwer&#8217;s Fixed-Point Theorem, which was proved by Shapley in 1973 in the context of game theory.<\/p>\n<p>We prove a colorful and polytopal generalization of the KKMS Theorem, and show that our theorem implies some seemingly unrelated results in discrete geometry and combinatorics involving colorful settings.<\/p>\n<p>For example, we apply our theorem to provide a new proof of the Colorful Caratheodory Theorem due to Barany, which asserts that if 0 is in the convex hull of n+1 sets of points in R^n, then there exists a colorful selection of points, one from each set, containing 0 in its convex hull. We further apply our theorem to obtain an upper bound on the piercing numbers in colorful d-interval families, extending results of Tardos, Kaiser and Alon for the non-colored case. Finally, we apply our theorem to questions regarding envy-free fair division of goods (e.g., cakes) among a set of players.<\/p>\n<p>Joint with Florian Frick.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The topological KKMS Theorem is a powerful extension of the Brouwer&#8217;s Fixed-Point Theorem, which was proved by Shapley in 1973 in the context of game theory. We prove a colorful and polytopal generalization of the KKMS Theorem, and show that&#8230;<br \/><a class=\"read-more-button\" href=\"https:\/\/mathematics.haifa.ac.il\/?p=968\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-968","post","type-post","status-publish","format-standard","hentry","category-colloquium"],"_links":{"self":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts\/968","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=968"}],"version-history":[{"count":1,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts\/968\/revisions"}],"predecessor-version":[{"id":969,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts\/968\/revisions\/969"}],"wp:attachment":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=968"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=968"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=968"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}