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	<title>Primeness is contraction-closed - Revision history</title>
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	<updated>2026-04-23T10:09:44Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
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		<id>https://commalg.subwiki.org/w/index.php?title=Primeness_is_contraction-closed&amp;diff=997&amp;oldid=prev</id>
		<title>Vipul: 1 revision</title>
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		<updated>2008-05-12T16:33:14Z</updated>

		<summary type="html">&lt;p&gt;1 revision&lt;/p&gt;
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				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;1&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 16:33, 12 May 2008&lt;/td&gt;
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		<author><name>Vipul</name></author>
	</entry>
	<entry>
		<id>https://commalg.subwiki.org/w/index.php?title=Primeness_is_contraction-closed&amp;diff=996&amp;oldid=prev</id>
		<title>Vipul: New page: {{curing-ideal metaproperty satisfaction}}  ==Statement==  ===Property-theoretic statement===  The property of ideals in commutative unital rings of being a prime ideal satisfies t...</title>
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		<updated>2008-01-24T15:07:06Z</updated>

		<summary type="html">&lt;p&gt;New page: {{curing-ideal metaproperty satisfaction}}  ==Statement==  ===Property-theoretic statement===  The &lt;a href=&quot;/w/index.php?title=Property_of_ideals_in_commutative_unital_rings&amp;amp;action=edit&amp;amp;redlink=1&quot; class=&quot;new&quot; title=&quot;Property of ideals in commutative unital rings (page does not exist)&quot;&gt;property of ideals in commutative unital rings&lt;/a&gt; of being a &lt;a href=&quot;/wiki/Prime_ideal&quot; title=&quot;Prime ideal&quot;&gt;prime ideal&lt;/a&gt; satisfies t...&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{{curing-ideal metaproperty satisfaction}}&lt;br /&gt;
&lt;br /&gt;
==Statement==&lt;br /&gt;
&lt;br /&gt;
===Property-theoretic statement===&lt;br /&gt;
&lt;br /&gt;
The [[property of ideals in commutative unital rings]] of being a [[prime ideal]] satisfies the [[metaproperty of ideals in commutative unital rings]] of being [[contraction-closed property of ideals in commutative unital rings|contraction-closed]].&lt;br /&gt;
&lt;br /&gt;
===Verbal statement===&lt;br /&gt;
&lt;br /&gt;
Given a [[homomorphism of commutative unital rings]], the [[contraction]] of a [[prime ideal]] in the ring on the right, is a prime ideal in the ring on the left.&lt;br /&gt;
&lt;br /&gt;
===Symbolic statement===&lt;br /&gt;
&lt;br /&gt;
Suppose &amp;lt;math&amp;gt;f:R \to S&amp;lt;/math&amp;gt; is a [[homomorphism of commutative unital rings]]. Then for any [[prime ideal]] &amp;lt;math&amp;gt;I&amp;lt;/math&amp;gt; of &amp;lt;math&amp;gt;S&amp;lt;/math&amp;gt;, &amp;lt;math&amp;gt;I^c = f^{-1}(I)&amp;lt;/math&amp;gt; (called the [[contraction]] of &amp;lt;math&amp;gt;I&amp;lt;/math&amp;gt;) is a prime ideal of &amp;lt;math&amp;gt;R&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Importance==&lt;br /&gt;
&lt;br /&gt;
This fact allows us to view the [[spectrum]] of a commutative unital ring as a contravariant functor, because it allows us to use a [[homomorphism of commutative unital rings]] &amp;lt;math&amp;gt;f:R \to S&amp;lt;/math&amp;gt; to define a backward map &amp;lt;math&amp;gt;Spec(f): Spec(S) \to Spec(R)&amp;lt;/math&amp;gt;, by contraction.&lt;br /&gt;
&lt;br /&gt;
==Proof==&lt;br /&gt;
&lt;br /&gt;
{{fillin}}&lt;/div&gt;</summary>
		<author><name>Vipul</name></author>
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