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	<id>https://drorbn.net/index.php?action=history&amp;feed=atom&amp;title=Knot_at_Lunch_on_December_12_2007</id>
	<title>Knot at Lunch on December 12 2007 - Revision history</title>
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	<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Knot_at_Lunch_on_December_12_2007&amp;action=history"/>
	<updated>2026-06-22T01:07:20Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
	<generator>MediaWiki 1.39.6</generator>
	<entry>
		<id>https://drorbn.net/index.php?title=Knot_at_Lunch_on_December_12_2007&amp;diff=6007&amp;oldid=prev</id>
		<title>Drorbn at 18:28, 12 December 2007</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Knot_at_Lunch_on_December_12_2007&amp;diff=6007&amp;oldid=prev"/>
		<updated>2007-12-12T18:28:49Z</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;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&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 14:28, 12 December 2007&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 18:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 18:&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;==Bone Soup==&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;==Bone Soup==&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;Let &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; be a natural number and let &amp;lt;math&amp;gt;R={\mathbb Z}[x_1,\ldots,x_n]&amp;lt;/math&amp;gt; be the ring of polynomials in &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; variables &amp;lt;math&amp;gt;x_1,\ldots,x_n&amp;lt;/math&amp;gt;. &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;Let&lt;/del&gt; &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;be&lt;/del&gt; the &amp;lt;math&amp;gt;R&amp;lt;/math&amp;gt;-module generated by symbols &amp;lt;math&amp;gt;B_{ij;kl}&amp;lt;/math&amp;gt; (the &quot;bones&quot;) where &amp;lt;math&amp;gt;1\leq i,j,k,l\leq n&amp;lt;/math&amp;gt;, subject to the relations:&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;Let &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; be a natural number and let &amp;lt;math&amp;gt;R={\mathbb Z}[x_1,\ldots,x_n]&amp;lt;/math&amp;gt; be the ring of polynomials in &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; variables &amp;lt;math&amp;gt;x_1,\ldots,x_n&amp;lt;/math&amp;gt;. &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;The &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt;&#039;th bone soup module&lt;/ins&gt; &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;is&lt;/ins&gt; the &amp;lt;math&amp;gt;R&amp;lt;/math&amp;gt;-module generated by symbols &amp;lt;math&amp;gt;B_{ij;kl}&amp;lt;/math&amp;gt; (the &quot;bones&quot;) where &amp;lt;math&amp;gt;1\leq i,j,k,l\leq n&amp;lt;/math&amp;gt;, subject to the relations:&lt;/div&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;math&amp;gt;B_{ij;kl}=B_{kl;ij}=-B_{ji;kl}=-B_{ij;lk}&amp;lt;/math&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;math&amp;gt;B_{ij;kl}=B_{kl;ij}=-B_{ji;kl}=-B_{ij;lk}&amp;lt;/math&amp;gt;.&lt;/div&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;math&amp;gt;x_mB_{ij;kl}-x_jB_{im;kl}+x_iB_{jm;kl}=0&amp;lt;/math&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;math&amp;gt;x_mB_{ij;kl}-x_jB_{im;kl}+x_iB_{jm;kl}=0&amp;lt;/math&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=Knot_at_Lunch_on_December_12_2007&amp;diff=6006&amp;oldid=prev</id>
		<title>Drorbn at 17:06, 12 December 2007</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Knot_at_Lunch_on_December_12_2007&amp;diff=6006&amp;oldid=prev"/>
		<updated>2007-12-12T17:06:06Z</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;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&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 13:06, 12 December 2007&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 18:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 18:&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;==Bone Soup==&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;==Bone Soup==&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;Let &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; be a natural number and let &amp;lt;math&amp;gt;R={\mathbb Z}[x_1,\ldots,x_n]&amp;lt;/math&amp;gt; be the ring of polynomials &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;on&lt;/del&gt; &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;generators&lt;/del&gt; &amp;lt;math&amp;gt;x_1,\ldots,x_n&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;R&amp;lt;/math&amp;gt;-module generated by symbols &amp;lt;math&amp;gt;B_{ij;kl}&amp;lt;/math&amp;gt; (the &quot;bones&quot;) where &amp;lt;math&amp;gt;1\leq i,j,k,l\leq n&amp;lt;/math&amp;gt;, subject to the relations:&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;Let &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; be a natural number and let &amp;lt;math&amp;gt;R={\mathbb Z}[x_1,\ldots,x_n]&amp;lt;/math&amp;gt; be the ring of polynomials &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;in&lt;/ins&gt; &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;variables&lt;/ins&gt; &amp;lt;math&amp;gt;x_1,\ldots,x_n&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;R&amp;lt;/math&amp;gt;-module generated by symbols &amp;lt;math&amp;gt;B_{ij;kl}&amp;lt;/math&amp;gt; (the &quot;bones&quot;) where &amp;lt;math&amp;gt;1\leq i,j,k,l\leq n&amp;lt;/math&amp;gt;, subject to the relations:&lt;/div&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;math&amp;gt;B_{ij;kl}=B_{kl;ij}=-B_{ji;kl}=-B_{ij;lk}&amp;lt;/math&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;math&amp;gt;B_{ij;kl}=B_{kl;ij}=-B_{ji;kl}=-B_{ij;lk}&amp;lt;/math&amp;gt;.&lt;/div&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;math&amp;gt;x_mB_{ij;kl}-x_jB_{im;kl}+x_iB_{jm;kl}=0&amp;lt;/math&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;math&amp;gt;x_mB_{ij;kl}-x_jB_{im;kl}+x_iB_{jm;kl}=0&amp;lt;/math&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=Knot_at_Lunch_on_December_12_2007&amp;diff=6004&amp;oldid=prev</id>
		<title>Drorbn at 16:24, 12 December 2007</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Knot_at_Lunch_on_December_12_2007&amp;diff=6004&amp;oldid=prev"/>
		<updated>2007-12-12T16:24:29Z</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;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&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 12:24, 12 December 2007&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 23:&lt;/td&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 23:&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;&#039;&#039;&#039;Question 1.&#039;&#039;&#039; Can you find a simple basis for &amp;lt;math&amp;gt;B_n&amp;lt;/math&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;&#039;&#039;&#039;Question 1.&#039;&#039;&#039; Can you find a simple basis for &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt;?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;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;&#039;&#039;&#039;Question 2.&#039;&#039;&#039; Is &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; related to curvature tensors and Bianchi identities?&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;&#039;&#039;&#039;Question 2.&#039;&#039;&#039; Is &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; related to curvature tensors and Bianchi identities?&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=Knot_at_Lunch_on_December_12_2007&amp;diff=6003&amp;oldid=prev</id>
		<title>Drorbn at 16:24, 12 December 2007</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Knot_at_Lunch_on_December_12_2007&amp;diff=6003&amp;oldid=prev"/>
		<updated>2007-12-12T16:24:15Z</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;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;tr class=&quot;diff-title&quot; lang=&quot;en&quot;&gt;
				&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 12:24, 12 December 2007&lt;/td&gt;
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  &lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 16:&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;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;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;Dror.&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;Dror.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;==Bone Soup==&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;Let &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; be a natural number and let &amp;lt;math&amp;gt;R={\mathbb Z}[x_1,\ldots,x_n]&amp;lt;/math&amp;gt; be the ring of polynomials on &amp;lt;math&amp;gt;n&amp;lt;/math&amp;gt; generators &amp;lt;math&amp;gt;x_1,\ldots,x_n&amp;lt;/math&amp;gt;. Let &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; be the &amp;lt;math&amp;gt;R&amp;lt;/math&amp;gt;-module generated by symbols &amp;lt;math&amp;gt;B_{ij;kl}&amp;lt;/math&amp;gt; (the &quot;bones&quot;) where &amp;lt;math&amp;gt;1\leq i,j,k,l\leq n&amp;lt;/math&amp;gt;, subject to the relations:&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;* &amp;lt;math&amp;gt;B_{ij;kl}=B_{kl;ij}=-B_{ji;kl}=-B_{ij;lk}&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;* &amp;lt;math&amp;gt;x_mB_{ij;kl}-x_jB_{im;kl}+x_iB_{jm;kl}=0&amp;lt;/math&amp;gt;.&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;br /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;Question 1.&#039;&#039;&#039; Can you find a simple basis for &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt;?&lt;/div&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
  &lt;td colspan=&quot;2&quot; class=&quot;diff-empty diff-side-deleted&quot;&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;Question 2.&#039;&#039;&#039; Is &amp;lt;math&amp;gt;B_n&amp;lt;/math&amp;gt; related to curvature tensors and Bianchi identities?&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=Knot_at_Lunch_on_December_12_2007&amp;diff=5999&amp;oldid=prev</id>
		<title>Drorbn at 15:53, 10 December 2007</title>
		<link rel="alternate" type="text/html" href="https://drorbn.net/index.php?title=Knot_at_Lunch_on_December_12_2007&amp;diff=5999&amp;oldid=prev"/>
		<updated>2007-12-10T15:53:37Z</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;{{KAL/Navigation}}&lt;br /&gt;
&lt;br /&gt;
==Invitation==&lt;br /&gt;
&lt;br /&gt;
Dear Knot at Lunch People,&lt;br /&gt;
&lt;br /&gt;
We will have our next fall lunch on Wednesday December 12, at the usual place, Bahen 6180, at 12 noon.&lt;br /&gt;
&lt;br /&gt;
As always, please bring brown-bag lunch and fresh ideas. This is break time, and I expect relatively low attendance. So whatever we will do, it will be light and easy.&lt;br /&gt;
&lt;br /&gt;
Further information about this meeting will/may appear at &amp;lt;span class=&amp;quot;plainlinks&amp;quot;&amp;gt;{{SERVER}}/drorbn/index.php?title={{PAGENAMEE}}&amp;lt;/span&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
As always, if you know anyone I should add to this mailing list or if you wish to be removed from this mailing list please let me know. To prevent junk accumulation in mailboxes, I will actively remove inactive people unless they request otherwise.&lt;br /&gt;
&lt;br /&gt;
Best,&lt;br /&gt;
&lt;br /&gt;
Dror.&lt;/div&gt;</summary>
		<author><name>Drorbn</name></author>
	</entry>
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