{"id":14575,"date":"2016-03-01T19:18:47","date_gmt":"2016-03-01T19:18:47","guid":{"rendered":"http:\/\/www.oracletutoring.ca\/blog\/?p=14575"},"modified":"2016-03-01T19:18:47","modified_gmt":"2016-03-01T19:18:47","slug":"math-comp-sci-graph-theory-complete-graph","status":"publish","type":"post","link":"https:\/\/www.oracletutoring.ca\/blog\/math-comp-sci-graph-theory-complete-graph\/","title":{"rendered":"Math &#038; Comp Sci:  Graph theory:  Complete graph"},"content":{"rendered":"<h1>The tutor introduces the idea of the complete graph.<\/h1>\n<p>The complete graph on n vertices, K<sub>n<\/sub>, means the graph in which each vertex is connected to each other one.<\/p>\n<p>When two vertices are connected by an edge, they can be called adjacent.  Therefore, the complete graph K<sub>n<\/sub> has n vertices, each adjacent to all the others.<\/p>\n<p>With K<sub>n<\/sub>, the degree of each vertex (meaning the number of other vertices to which it is adjacent) is n-1.  The number of edges, |E|, for K<sub>n<\/sub> can be gotten two ways:<\/p>\n<ol>\n<li>|E| = nC2.  Reason:  each edge joins a pair of vertices.  Therefore, for K<sub>n<\/sub>, the number of edges is the number of possible pairs of vertices, which is nC2.\n<\/li>\n<p>&NewLine;<\/p>\n<li>\nFor any graph, the sum of the degrees of the vertices is twice the number of edges:  &sum;deg(v) = 2|E|.  Then, for K<sub>n<\/sub>, &sum;deg(v)=n(n-1)=2|E|, which means<br \/>n(n-1)\/2 = |E|.\n<\/li>\n<\/ol>\n<p>Reassuringly, nC2 = n(n-1)\/2.<\/p>\n<p>HTH:)<\/p>\n<p>Source:<\/p>\n<p>Grimaldi, Ralph P.  <u>Discrete and Combinatorial Mathematics<\/u>.  Don Mills:  Addison-<br \/>&nbsp;&nbsp;Wesley, 1994.<\/p>\n<p>Jack of <a href=\"https:\/\/www.oracletutoring.ca\">Oracle Tutoring by Jack and Diane,<\/a> Campbell River, BC.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The tutor introduces the idea of the complete graph. The complete graph on n vertices, Kn, means the graph in which each vertex is connected to each other one. When two vertices are connected by an edge, they can be &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"more-link\" href=\"https:\/\/www.oracletutoring.ca\/blog\/math-comp-sci-graph-theory-complete-graph\/\"> <span class=\"screen-reader-text\">Math &#038; Comp Sci:  Graph theory:  Complete graph<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[105,3],"tags":[1470,1471,1467,1444,1469,1468],"class_list":["post-14575","post","type-post","status-publish","format-standard","hentry","category-computer-science","category-math","tag-adjacent-vertices","tag-complete-graph","tag-degree-of-a-vertex","tag-graph-theory","tag-kn","tag-number-of-edges-of-complete-graph"],"_links":{"self":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/14575","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/comments?post=14575"}],"version-history":[{"count":15,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/14575\/revisions"}],"predecessor-version":[{"id":14590,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/14575\/revisions\/14590"}],"wp:attachment":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/media?parent=14575"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/categories?post=14575"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/tags?post=14575"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}