<html xmlns="http://www.w3.org/1999/xhtml"><head></head><body><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="1" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[1]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">環</anchor> <code class="math"><var>R</var></code> が<dfn>可換環</dfn>であるとは:<ul><li><code class="math">(∀<var>a</var>, <var>b</var> ∈ <var>R</var>) <var>a</var><var>b</var> = <var>b</var><var>a</var></code>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">積</anchor>に関する<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">交換法則</anchor>)</li></ul></p></body></html>