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	<id>https://drorbn.net/index.php?action=history&amp;feed=atom&amp;title=0708-1300%2FHomework_Assignment_8</id>
	<title>0708-1300/Homework Assignment 8 - Revision history</title>
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	<updated>2026-06-19T14:08:20Z</updated>
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	<entry>
		<id>https://drorbn.net/index.php?title=0708-1300/Homework_Assignment_8&amp;diff=6216&amp;oldid=prev</id>
		<title>Drorbn at 14:51, 24 January 2008</title>
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		<updated>2008-01-24T14:51:28Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 10:51, 24 January 2008&lt;/td&gt;
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  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;
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  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
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  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Reading==&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Reading==&lt;/div&gt;&lt;/td&gt;
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&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=0708-1300/Homework_Assignment_8&amp;diff=6215&amp;oldid=prev</id>
		<title>Drorbn at 14:49, 24 January 2008</title>
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		<updated>2008-01-24T14:49:46Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 10:49, 24 January 2008&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 6:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 6:&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Doing==&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Doing==&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;Just one problem.&#039;&#039;&#039; Let &amp;lt;math&amp;gt;K&amp;lt;/math&amp;gt; be a knot in &amp;lt;math&amp;gt;{\mathbb R}^3&amp;lt;/math&amp;gt; presented by a planar diagram &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt;. With a massive use of Van-Kampen&#039;s theorem, show that the fundamental group of the complement of &amp;lt;math&amp;gt;K&amp;lt;/math&amp;gt; has a presentation (the &quot;Wirtinger&quot;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt; [http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Wirtinger.html] [http://en.wikipedia.org/wiki/Wirtinger]&lt;/del&gt; presentation) with one generator for each edge of &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; and two relations for each crossing of &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt;, as indicated in the figure below.&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;Just one problem.&#039;&#039;&#039; Let &amp;lt;math&amp;gt;K&amp;lt;/math&amp;gt; be a knot in &amp;lt;math&amp;gt;{\mathbb R}^3&amp;lt;/math&amp;gt; presented by a planar diagram &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt;. With a massive use of Van-Kampen&#039;s theorem, show that the fundamental group of the complement of &amp;lt;math&amp;gt;K&amp;lt;/math&amp;gt; has a presentation (the &quot;Wirtinger&quot; presentation) with one generator for each edge of &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; and two relations for each crossing of &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt;, as indicated in the figure below.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
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  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
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  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;center&amp;gt;&lt;/div&gt;&lt;/td&gt;
  &lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;
  &lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;lt;center&amp;gt;&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
	<entry>
		<id>https://drorbn.net/index.php?title=0708-1300/Homework_Assignment_8&amp;diff=6213&amp;oldid=prev</id>
		<title>Drorbn at 14:44, 24 January 2008</title>
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		<updated>2008-01-24T14:44:07Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{{0708-1300/Navigation}}&lt;br /&gt;
{{In Preparation}}&lt;br /&gt;
&lt;br /&gt;
==Reading==&lt;br /&gt;
Read, reread and rereread your notes to this point, and make sure that you really, really really, really really really understand everything in them. Do the same every week!&lt;br /&gt;
&lt;br /&gt;
==Doing==&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Just one problem.&amp;#039;&amp;#039;&amp;#039; Let &amp;lt;math&amp;gt;K&amp;lt;/math&amp;gt; be a knot in &amp;lt;math&amp;gt;{\mathbb R}^3&amp;lt;/math&amp;gt; presented by a planar diagram &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt;. With a massive use of Van-Kampen&amp;#039;s theorem, show that the fundamental group of the complement of &amp;lt;math&amp;gt;K&amp;lt;/math&amp;gt; has a presentation (the &amp;quot;Wirtinger&amp;quot; [http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Wirtinger.html] [http://en.wikipedia.org/wiki/Wirtinger] presentation) with one generator for each edge of &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt; and two relations for each crossing of &amp;lt;math&amp;gt;D&amp;lt;/math&amp;gt;, as indicated in the figure below.&lt;br /&gt;
&lt;br /&gt;
&amp;lt;center&amp;gt;&lt;br /&gt;
[[Image:0708-1300-WirtingerExample.png]]&lt;br /&gt;
&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Due Date==&lt;br /&gt;
This assignment is due in class on Thursday February 7, 2008.&lt;/div&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
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