{"id":187,"date":"2019-12-13T10:47:40","date_gmt":"2019-12-13T15:47:40","guid":{"rendered":"http:\/\/blogs.uml.edu\/cotangents\/?p=187"},"modified":"2020-01-11T10:11:25","modified_gmt":"2020-01-11T15:11:25","slug":"whats-your-favorite-theorem","status":"publish","type":"post","link":"https:\/\/blogs.uml.edu\/cotangents\/2019\/12\/13\/whats-your-favorite-theorem\/","title":{"rendered":"What&#8217;s Your Favorite Theorem?"},"content":{"rendered":"\n \n<p>A while ago I discovered a Podcast called <a href=\"https:\/\/kpknudson.com\/my-favorite-theorem\" target=\"_new\" rel=\"noopener noreferrer\">My Favorite Theorem<\/a> and have eagerly listened to each new episode. The basic format is that a mathematician is invited by the two hosts (Kevin Knudson and Evelyn Lamb) to describe his\/her favorite theorem and also to pair the theorem with some non-mathematical thing, usually food or music.<\/p>\n<p>What&#8217;s <em>your<\/em> favorite theorem? &nbsp;Mine is the Chinese Remainder Theorem. &nbsp;It&#8217;s got an obvious pairing, but that isn&#8217;t why I picked it. &nbsp;My reason is that is appears in several courses I&#8217;ve taught and also has connections with my dissertation research way back in the 1970&#8217;s.<\/p>\n<p>In an abstract algebra course, the Chinese Remainder Theorem says that if two positive integers, <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-6b41df788161942c6f98604d37de8098_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"15\" style=\"vertical-align: 0px;\"\/> and <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-b170995d512c659d8668b4e42e1fef6b_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"11\" style=\"vertical-align: 0px;\"\/>, are relatively prime, then the ring of integers mod <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-b6e5769de7136496e54aa8e487031fe9_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;&#32;&#92;&#99;&#100;&#111;&#116;&#32;&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"39\" style=\"vertical-align: 0px;\"\/> is isomorphic to the direct product the rings of integers mod <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-6b41df788161942c6f98604d37de8098_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"15\" style=\"vertical-align: 0px;\"\/> and <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-b170995d512c659d8668b4e42e1fef6b_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"11\" style=\"vertical-align: 0px;\"\/>.<\/p>\n<p>In number theory, the same fact is framed differently, that the system of congruences <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-72843b19e1edca02107bb1c4ce6b5278_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#120;&#32;&#92;&#101;&#113;&#117;&#105;&#118;&#32;&#97;&#32;&#92;&#112;&#109;&#111;&#100;&#123;&#109;&#125;\" title=\"Rendered by QuickLaTeX.com\" height=\"18\" width=\"120\" style=\"vertical-align: -4px;\"\/> and <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-8b7f7911e95dca005b351c9cd1efda1e_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#120;&#32;&#92;&#101;&#113;&#117;&#105;&#118;&#32;&#98;&#32;&#92;&#112;&#109;&#111;&#100;&#123;&#110;&#125;\" title=\"Rendered by QuickLaTeX.com\" height=\"18\" width=\"113\" style=\"vertical-align: -4px;\"\/> always has a unique solution mod <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-4c51a2cca66b15acd9c6bae6d261b014_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;&#92;&#99;&#100;&#111;&#116;&#32;&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"39\" style=\"vertical-align: 0px;\"\/> as long as <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-6b41df788161942c6f98604d37de8098_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#109;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"15\" style=\"vertical-align: 0px;\"\/> and <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-b170995d512c659d8668b4e42e1fef6b_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"11\" style=\"vertical-align: 0px;\"\/> are relatively prime.<\/p>\n<p>My dissertation research involved approximation and interpolation of functions, and when you generalize the Chinese Remainder Theorem to Euclidean Domains, one immediate implication is that given <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-d72f4e3699652cfc70b8880515893d7c_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#110;&#43;&#49;\" title=\"Rendered by QuickLaTeX.com\" height=\"14\" width=\"40\" style=\"vertical-align: -2px;\"\/> points on the plane (pick any field) with distinct <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-ede05c264bba0eda080918aaa09c4658_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#120;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"10\" style=\"vertical-align: 0px;\"\/>-values, there is always a unique polynomial of degree <img loading=\"lazy\" src=\"https:\/\/blogs.uml.edu\/cotangents\/wp-content\/ql-cache\/quicklatex.com-b170995d512c659d8668b4e42e1fef6b_l3.png\" class=\"ql-img-inline-formula quicklatex-auto-format\" alt=\"&#110;\" title=\"Rendered by QuickLaTeX.com\" height=\"8\" width=\"11\" style=\"vertical-align: 0px;\"\/> or less that passes through the points.<\/p>\n<p>If you have a favorite theorem feel free to post it in the comments!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>What&#8217;s your favorite theorem? Mine is the Chinese Remainder Theorem. <a href=\"https:\/\/blogs.uml.edu\/cotangents\/2019\/12\/13\/whats-your-favorite-theorem\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":331,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[81],"_links":{"self":[{"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/posts\/187"}],"collection":[{"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/users\/331"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/comments?post=187"}],"version-history":[{"count":26,"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/posts\/187\/revisions"}],"predecessor-version":[{"id":287,"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/posts\/187\/revisions\/287"}],"wp:attachment":[{"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/media?parent=187"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/categories?post=187"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.uml.edu\/cotangents\/wp-json\/wp\/v2\/tags?post=187"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}