Namespaces
Variants
Actions

Difference between revisions of "Commutator"

From Encyclopedia of Mathematics
Jump to: navigation, search
(Importing text file)
 
(TeX)
 
Line 1: Line 1:
''of two elements <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234301.png" /> and <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234302.png" /> in a group with multiple operators''
+
{{TEX|done}}
 +
''of two elements $a$ and $b$ in a group with multiple operators''
  
 
The element
 
The element
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234303.png" /></td> </tr></table>
+
$$-a-b+a+b.$$
  
For groups without multiple operators (here the operation is usually called multiplication), the commutator of the elements <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234304.png" /> and <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234305.png" /> is the element <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234306.png" />. The set of all commutators in a group <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234307.png" /> generates a subgroup, called the [[Commutator subgroup|commutator subgroup]] of <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234308.png" />.
+
For groups without multiple operators (here the operation is usually called multiplication), the commutator of the elements $a$ and $b$ is the element $a^{-1}b^{-1}ab$. The set of all commutators in a group $G$ generates a subgroup, called the [[Commutator subgroup|commutator subgroup]] of $G$.
  
In an associative algebra the element <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c0234309.png" /> is called the Lie product, or commutator, of <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c02343010.png" /> and <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/c/c023/c023430/c02343011.png" />.
+
In an associative algebra the element $[x,y]=xy-yx$ is called the Lie product, or commutator, of $x$ and $y$.

Latest revision as of 14:01, 10 April 2014

of two elements $a$ and $b$ in a group with multiple operators

The element

$$-a-b+a+b.$$

For groups without multiple operators (here the operation is usually called multiplication), the commutator of the elements $a$ and $b$ is the element $a^{-1}b^{-1}ab$. The set of all commutators in a group $G$ generates a subgroup, called the commutator subgroup of $G$.

In an associative algebra the element $[x,y]=xy-yx$ is called the Lie product, or commutator, of $x$ and $y$.

How to Cite This Entry:
Commutator. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Commutator&oldid=16944
This article was adapted from an original article by O.A. Ivanova (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article