User Tools

Site Tools


definition:permutation_group

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
definition:permutation_group [2013/08/20 10:37]
bmwoodruff
definition:permutation_group [2013/08/30 11:47] (current)
joshuawiscons [External links]
Line 1: Line 1:
 ====== Permutation Group ====== ====== Permutation Group ======
 ====Definition====  ====Definition==== 
-Let $X$ be any set. A $\textdef{permutation group}$ on $X$ is any [[definition:subgroup]] of $\sym{X}$; that is, it is a subset of $\sym{X}$ that contains the identity and is closed under composition and taking inverses+A $\textdef{permutation group}$ on $X$ is a set of [[definition:permutation]]of $X$ that contains the identity permutation and is closed under function composition and taking inverses.
- +
-====Definition 2==== +
-Let $X$ be any set. A permutation on $X$ is a bijection from $X$ to $X$.  A $\textdef{permutation group}$ on $X$ is a set of permutations on $X$ that forms a group under function composition+
  
 ---- ----
 ==== Remarks ====  ==== Remarks ==== 
-  * $\sym{X}$ denotes the [[definition:symmetric group]] on $X$+  * Alternately, a permutation group is a subgroup of $\sym{X}$, where $\sym{X}$ denotes the [[definition:symmetric group]] on $X$.
-  * The first definition requires that we first define symmetric group, subgroup, and that we have developed some intuition about how to show something is a subgroup. The second definition avoids this.+
  
  
Line 17: Line 13:
 %%%%% %%%%%
 % DEPENDENCIES  % DEPENDENCIES 
-% RequiredMacros: \newcommand{\textdef}[1]{\textit{#1}}  \DeclareMathOperator{\sym}{Sym+% RequiredMacros: \newcommand{\textdef}[1]{\textit{#1}}
 %%%%% %%%%%
 \begin{definition} \begin{definition}
-Let $X$ be any set. A \textdef{permutation group} on $X$ is any subgroup of $\sym{X}$; that is, it is a subset of $\sym{X}$ that contains the identity and is closed under composition and taking inverses.+A \textdef{permutation group} on $X$ is a set of permutations of $X$ that contains the identity permutation and is closed under function composition and taking inverses.
 \end{definition} \end{definition}
 </file> </file>
Line 29: Line 25:
  
  
-{{tag>definition needsreview rben}}+{{tag>definition needsreview rben ben rjosh}}
definition/permutation_group.1377009452.txt.gz · Last modified: 2013/08/20 10:37 by bmwoodruff