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		<id>http://helmut.knaust.info/mediawiki/index.php?action=history&amp;feed=atom&amp;title=CRN_12107%3A_HW_6</id>
		<title>CRN 12107: HW 6 - Revision history</title>
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		<updated>2026-05-05T09:48:48Z</updated>
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	<entry>
		<id>http://helmut.knaust.info/mediawiki/index.php?title=CRN_12107:_HW_6&amp;diff=916&amp;oldid=prev</id>
		<title>HelmutKnaust at 21:00, 15 November 2013</title>
		<link rel="alternate" type="text/html" href="http://helmut.knaust.info/mediawiki/index.php?title=CRN_12107:_HW_6&amp;diff=916&amp;oldid=prev"/>
				<updated>2013-11-15T21:00:05Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table class='diff diff-contentalign-left'&gt;
				&lt;col class='diff-marker' /&gt;
				&lt;col class='diff-content' /&gt;
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			&lt;td colspan='2' style=&quot;background-color: white; color:black;&quot;&gt;← Older revision&lt;/td&gt;
			&lt;td colspan='2' style=&quot;background-color: white; color:black;&quot;&gt;Revision as of 21:00, 15 November 2013&lt;/td&gt;
			&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 4:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 4:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;'''Problem 27.'''&amp;#160; Let $R$ be a relation on $\mathbb{N}$ defined by &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;'''Problem 27.'''&amp;#160; Let $R$ be a relation on $\mathbb{N}$ defined by &amp;#160;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;background: #ffa; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;\[(&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;m&lt;/del&gt;,&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;n&lt;/del&gt;)\in R \Leftrightarrow &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;m&lt;/del&gt;^2+&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;n&lt;/del&gt;^2 \mbox{ is even.}\]&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;background: #cfc; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;\[(&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;p&lt;/ins&gt;,&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;q&lt;/ins&gt;)\in R \Leftrightarrow &lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;p&lt;/ins&gt;^2+&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;q&lt;/ins&gt;^2 \mbox{ is even.}\]&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;#Show that $R$ is an equivalence relation.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;#Show that $R$ is an equivalence relation.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;#Find all distinct equivalence classes of this relation.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;&amp;#160;&lt;/td&gt;&lt;td style=&quot;background: #eee; color:black; font-size: smaller;&quot;&gt;&lt;div&gt;#Find all distinct equivalence classes of this relation.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>HelmutKnaust</name></author>	</entry>

	<entry>
		<id>http://helmut.knaust.info/mediawiki/index.php?title=CRN_12107:_HW_6&amp;diff=891&amp;oldid=prev</id>
		<title>HelmutKnaust: Created page with &quot;'''Problem 26.'''  Consider the following equivalence relation on the set $A=\{1,2,3,4,5,6\}$: \[R=\{(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(1,2),(1,4),(2,1),(2,4),(4,1),(4,2),(3...&quot;</title>
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				<updated>2013-11-05T05:01:34Z</updated>
		
		<summary type="html">&lt;p&gt;Created page with &amp;quot;&amp;#039;&amp;#039;&amp;#039;Problem 26.&amp;#039;&amp;#039;&amp;#039;  Consider the following equivalence relation on the set $A=\{1,2,3,4,5,6\}$: \[R=\{(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(1,2),(1,4),(2,1),(2,4),(4,1),(4,2),(3...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;'''Problem 26.'''  Consider the following equivalence relation on the set $A=\{1,2,3,4,5,6\}$:&lt;br /&gt;
\[R=\{(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(1,2),(1,4),(2,1),(2,4),(4,1),(4,2),(3,6),(6,3)\}.\]&lt;br /&gt;
Find the partition generated by $R$.&lt;br /&gt;
&lt;br /&gt;
'''Problem 27.'''  Let $R$ be a relation on $\mathbb{N}$ defined by &lt;br /&gt;
\[(m,n)\in R \Leftrightarrow m^2+n^2 \mbox{ is even.}\]&lt;br /&gt;
#Show that $R$ is an equivalence relation.&lt;br /&gt;
#Find all distinct equivalence classes of this relation.&lt;br /&gt;
&lt;br /&gt;
'''Problem 28.'''  Let $R$ and $S$ be two equivalence relations on a non-empty set $X$. Prove or disprove: &lt;br /&gt;
#$R\cap S$ is an equivalence relation. &lt;br /&gt;
#$R\cup S$ is an equivalence relation. &lt;br /&gt;
&lt;br /&gt;
'''Problem 29.'''  A relation $R$ on a non-empty set $X$ is called ''reverse-transitive'' if &lt;br /&gt;
\[(a,b)\in R \wedge (b,c)\in R \Rightarrow (c,a)\in R \mbox{ for all } a,b,c \in X.\]&lt;br /&gt;
Show that a relation $R$ on a non-empty set $X$ is an equivalence relation if and only if it is reflexive and reverse-transitive.&lt;br /&gt;
&lt;br /&gt;
'''Problem 30.'''  Consider the following relation $R$ defined on a Boolean Algebra ${\cal A}$:&lt;br /&gt;
\[(P,Q)\in R \Leftrightarrow P\sqcup Q=Q\]&lt;br /&gt;
Prove or disprove: $R$ is (a) reflexive, (b) transitive, (c) symmetric,  (d) anti-symmetric.&lt;/div&gt;</summary>
		<author><name>HelmutKnaust</name></author>	</entry>

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