
{"id":97,"date":"2013-02-14T18:27:47","date_gmt":"2013-02-14T18:27:47","guid":{"rendered":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/?p=97"},"modified":"2013-07-16T13:33:15","modified_gmt":"2013-07-16T13:33:15","slug":"homework-6","status":"publish","type":"post","link":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/2013\/02\/14\/homework-6\/","title":{"rendered":"Homework 6"},"content":{"rendered":"<p>Due February 21.<\/p>\n<p>A. Let \\(p:E \\to B\\) be a regular cover.  The group of covering translations \\(\\mathrm{Aut}(p)\\) acts on \\(E\\).  Show that the orbit space of this action is homeomorphic to \\(B\\), i.e. \\(B \\cong E\/\\mathrm{Aut}(p) \\).<\/p>\n<p>B. Given a group \\(G\\) and a normal subgroup \\(N\\), show that there exists a normal covering space \\(E\\to B\\) with \\(\\pi_1(B) \\cong G\\) and \\(\\pi_1(E) \\cong N\\), and covering transformation group \\(\\mathrm{Aut}(p) \\cong G\/N\\).<\/p>\n<p>C.  For a path-connected, locally path-connected, and semilocally simply-connected space \\(B\\), call a path-connected covering space \\(E\\to B\\) <em>abelian<\/em> if it is normal and has abelian covering transformation group.  Show that \\(B\\) has an abelian covering that is &#8216;universal&#8217; in the sense that it covers every abelian cover of \\(B\\).  Find the universal abelian cover of \\(S^1 \\vee S^1\\).<\/p>\n<p>D. Construct a two-sheeted covering of the Klein bottle by the torus.<\/p>\n<p>E. Read the section in Hatcher about representing covering transformations by permutations.  Let \\(B\\) be the wedge of two circles, so that \\(\\pi_1(B) = \\langle a, b\\rangle\\).    Construct a three-sheeted cover corresponding to the representation \\(\\rho: \\pi_1(B) \\to S_3\\) given by \\(\\rho(a) = (2\\,3)\\) and \\(\\rho(b) = (1\\,2\\,3)\\).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Due February 21. A. Let \\(p:E \\to B\\) be a regular cover. The group of covering translations \\(\\mathrm{Aut}(p)\\) acts on \\(E\\). Show that the orbit space of this action is homeomorphic to \\(B\\), i.e. \\(B \\cong E\/\\mathrm{Aut}(p) \\). B. Given a group \\(G\\) and a normal subgroup \\(N\\), show that there exists a normal covering [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/posts\/97"}],"collection":[{"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/comments?post=97"}],"version-history":[{"count":12,"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/posts\/97\/revisions"}],"predecessor-version":[{"id":202,"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/posts\/97\/revisions\/202"}],"wp:attachment":[{"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/media?parent=97"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/categories?post=97"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pdhorn.expressions.syr.edu\/spring2013mat761\/wp-json\/wp\/v2\/tags?post=97"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}