<?xml version='1.0' encoding='UTF-8'?><?xml-stylesheet href="http://www.blogger.com/styles/atom.css" type="text/css"?><feed xmlns='http://www.w3.org/2005/Atom' xmlns:openSearch='http://a9.com/-/spec/opensearchrss/1.0/' xmlns:georss='http://www.georss.org/georss' xmlns:gd='http://schemas.google.com/g/2005' xmlns:thr='http://purl.org/syndication/thread/1.0'><id>tag:blogger.com,1999:blog-4166327854818209158</id><updated>2011-07-08T00:25:53.280-07:00</updated><category term='algebra manifold calculus'/><title type='text'>Space Resembling Euclidean</title><subtitle type='html'></subtitle><link rel='http://schemas.google.com/g/2005#feed' type='application/atom+xml' href='http://differentiablemanifold.blogspot.com/feeds/posts/default'/><link rel='self' type='application/atom+xml' href='http://www.blogger.com/feeds/4166327854818209158/posts/default?max-results=100'/><link rel='alternate' type='text/html' href='http://differentiablemanifold.blogspot.com/'/><link rel='hub' href='http://pubsubhubbub.appspot.com/'/><author><name>Barbara Sanford</name><uri>http://www.blogger.com/profile/16083975084961215008</uri><email>noreply@blogger.com</email><gd:image rel='http://schemas.google.com/g/2005#thumbnail' width='32' height='25' src='http://2.bp.blogspot.com/_YKSpcjntDeQ/THNXWwAFGbI/AAAAAAAAAAM/dEJwsC2qa1s/S220/MobiusStrip.png'/></author><generator version='7.00' uri='http://www.blogger.com'>Blogger</generator><openSearch:totalResults>2</openSearch:totalResults><openSearch:startIndex>1</openSearch:startIndex><openSearch:itemsPerPage>100</openSearch:itemsPerPage><entry><id>tag:blogger.com,1999:blog-4166327854818209158.post-8384626990985961943</id><published>2010-08-29T14:24:00.000-07:00</published><updated>2010-08-29T14:24:05.345-07:00</updated><title type='text'>A Brief Introduction to Manifolds</title><content type='html'>We could begin with a simple definition of a &lt;a="href="http: en.wikipedia.org="" manifold="" wiki=""&gt;&lt;a href="http://en.wikipedia.org/wiki/Manifold"&gt;manifold&lt;/a&gt;, the informal definition we find on wikipdia, &lt;a href="http://en.wikipedia.org/wiki/Topological_space" title="Topological space"&gt;space&lt;/a&gt; that is "modeled on" &lt;a href="http://en.wikipedia.org/wiki/Euclidean_space" title="Euclidean space"&gt;Euclidean space&lt;/a&gt;."&amp;nbsp; Even less formally, space that is based on square, straight space.&lt;/a="href="http:&gt;&lt;br /&gt;&lt;a="href="http: en.wikipedia.org="" manifold="" wiki=""&gt;&lt;br /&gt;&lt;/a="href="http:&gt;&lt;br /&gt;&lt;a="href="http: en.wikipedia.org="" manifold="" wiki=""&gt;Why do this?&amp;nbsp; Well, we know that Euclidean space is just one space, and mathematicians needed a formal way to discuss this, and to find a way to deal with how humans think about things on earth, which is, mostly treated as a Euclidean space, even though it is not.&amp;nbsp; So we call&amp;nbsp; this a manifold to keep in mind the reality that, on the scale of our lives, things are approximately Euclidean, but not really on the larger scale.&amp;nbsp;&amp;nbsp; Thus, the sphere* on which we live is a 2-manifold, since, in a local area, it approximates a 2-dimensional Euclidean space (not taking into account the vertical dimension, nor the time-like dimension).&lt;/a="href="http:&gt;&lt;br /&gt;&lt;a="href="http: en.wikipedia.org="" manifold="" wiki=""&gt;&lt;br /&gt;&lt;/a="href="http:&gt;&lt;br /&gt;&lt;a="href="http: en.wikipedia.org="" manifold="" wiki=""&gt;This allows us to do useful things, like measure distances in units that we recognize, or make maps (!) and atlases.&amp;nbsp; The non-Euclidean nature of our world becomes evident when we try to make a map that covers a large region.&amp;nbsp;&amp;nbsp; Cartographers then employ several methods to make maps that will work for one use or another, but are never quite right over the entire surface.&lt;/a="href="http:&gt;&lt;br /&gt;&lt;a="href="http: en.wikipedia.org="" manifold="" wiki=""&gt;&lt;br /&gt;&lt;/a="href="http:&gt;&lt;br /&gt;&lt;a="href="http: en.wikipedia.org="" manifold="" wiki=""&gt;&lt;br /&gt;&lt;/a="href="http:&gt;&lt;div class="blogger-post-footer"&gt;&lt;img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/4166327854818209158-8384626990985961943?l=differentiablemanifold.blogspot.com' alt='' /&gt;&lt;/div&gt;</content><link rel='replies' type='application/atom+xml' href='http://differentiablemanifold.blogspot.com/feeds/8384626990985961943/comments/default' title='Post Comments'/><link rel='replies' type='text/html' href='http://differentiablemanifold.blogspot.com/2010/08/brief-introduction-to-manifolds.html#comment-form' title='0 Comments'/><link rel='edit' type='application/atom+xml' href='http://www.blogger.com/feeds/4166327854818209158/posts/default/8384626990985961943'/><link rel='self' type='application/atom+xml' href='http://www.blogger.com/feeds/4166327854818209158/posts/default/8384626990985961943'/><link rel='alternate' type='text/html' href='http://differentiablemanifold.blogspot.com/2010/08/brief-introduction-to-manifolds.html' title='A Brief Introduction to Manifolds'/><author><name>Barbara Sanford</name><uri>http://www.blogger.com/profile/16083975084961215008</uri><email>noreply@blogger.com</email><gd:image rel='http://schemas.google.com/g/2005#thumbnail' width='32' height='25' src='http://2.bp.blogspot.com/_YKSpcjntDeQ/THNXWwAFGbI/AAAAAAAAAAM/dEJwsC2qa1s/S220/MobiusStrip.png'/></author><thr:total>0</thr:total></entry><entry><id>tag:blogger.com,1999:blog-4166327854818209158.post-8033113142709592324</id><published>2010-08-22T23:31:00.000-07:00</published><updated>2010-08-22T23:31:11.048-07:00</updated><category scheme='http://www.blogger.com/atom/ns#' term='algebra manifold calculus'/><title type='text'>Why is this blog here?  First post.</title><content type='html'>You can read more about differentiable manofolds on wikipedia: &lt;br /&gt;&lt;a href="http://en.wikipedia.org/wiki/Differentiable_manifold"&gt;http://en.wikipedia.org/wiki/Differentiable_manifold&lt;/a&gt;,&amp;nbsp;and that really is just an introduction. &amp;nbsp;Math is fun, and that article is just a taste. &lt;br /&gt;&lt;br /&gt;You may find some deep meaning in posts here, but not likely. &amp;nbsp;If you do, please tell me. &amp;nbsp;It may not be intentional. &amp;nbsp;Topics will not be limited to Math, but may include politics, economics, science (several), history. &amp;nbsp;&lt;br /&gt;&lt;br /&gt;Sports are off-topic, unless I decide otherwise.&lt;br /&gt;&lt;br /&gt;&lt;b&gt;trigger warning:&lt;/b&gt;&amp;nbsp;Arguments are likely. &lt;br /&gt;&lt;br /&gt;that is all for now.&lt;div class="blogger-post-footer"&gt;&lt;img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/4166327854818209158-8033113142709592324?l=differentiablemanifold.blogspot.com' alt='' /&gt;&lt;/div&gt;</content><link rel='replies' type='application/atom+xml' href='http://differentiablemanifold.blogspot.com/feeds/8033113142709592324/comments/default' title='Post Comments'/><link rel='replies' type='text/html' href='http://differentiablemanifold.blogspot.com/2010/08/why-is-this-blog-here-first-post.html#comment-form' title='0 Comments'/><link rel='edit' type='application/atom+xml' href='http://www.blogger.com/feeds/4166327854818209158/posts/default/8033113142709592324'/><link rel='self' type='application/atom+xml' href='http://www.blogger.com/feeds/4166327854818209158/posts/default/8033113142709592324'/><link rel='alternate' type='text/html' href='http://differentiablemanifold.blogspot.com/2010/08/why-is-this-blog-here-first-post.html' title='Why is this blog here?  First post.'/><author><name>Barbara Sanford</name><uri>http://www.blogger.com/profile/16083975084961215008</uri><email>noreply@blogger.com</email><gd:image rel='http://schemas.google.com/g/2005#thumbnail' width='32' height='25' src='http://2.bp.blogspot.com/_YKSpcjntDeQ/THNXWwAFGbI/AAAAAAAAAAM/dEJwsC2qa1s/S220/MobiusStrip.png'/></author><thr:total>0</thr:total></entry></feed>
