Symmetric group: Difference between revisions

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===Symbol-free definition===
===Symbol-free definition===


The '''symmetric group''' on a set is the group of all permutations of that set. A group is said to be a symmetric group if it is isomorphic to the symmetric group on some set.
The '''symmetric group''' on a set is the group of all permutations of that set (i.e., bijective maps from the set to itself). A group is said to be a symmetric group if it is isomorphic to the symmetric group on some set.


===Definition with symbols===
===Definition with symbols===
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A group <math>G</math> is termed a '''symmetric group''' if <math>G \cong Sym(S)</math> for some set <math>S</math>.
A group <math>G</math> is termed a '''symmetric group''' if <math>G \cong Sym(S)</math> for some set <math>S</math>.
A bijection between sets gives rise to an isomorphism of the corresponding symmetric groups. Thus, there is only one symmetric group, upto isomorphism, on a set of given cardinality. The symmetric group on a set of cardinality <math>n</math> is denoted <math>Sym(n)</math>, or sometimes <math>S_n</math>.


==Relation with other properties==
==Relation with other properties==

Revision as of 10:39, 16 June 2008

This article defines a group property: a property that can be evaluated to true/false for any given group, invariant under isomorphism
View a complete list of group properties
VIEW RELATED: Group property implications | Group property non-implications |Group metaproperty satisfactions | Group metaproperty dissatisfactions | Group property satisfactions | Group property dissatisfactions

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To get more information on particular symmetric groups, check out Category:Symmetric groups

Definition

Symbol-free definition

The symmetric group on a set is the group of all permutations of that set (i.e., bijective maps from the set to itself). A group is said to be a symmetric group if it is isomorphic to the symmetric group on some set.

Definition with symbols

The symmetric group over a set (denoted as ) is defined as the group of all permutations on , with the multiplication being function composition.

A group is termed a symmetric group if for some set .

A bijection between sets gives rise to an isomorphism of the corresponding symmetric groups. Thus, there is only one symmetric group, upto isomorphism, on a set of given cardinality. The symmetric group on a set of cardinality is denoted , or sometimes .

Relation with other properties

Weaker properties

Related notions

Alternating group

Finitary symmetric and alternating groups

Subgroups of the symmetric group

IAPS structure

Further information: Permutation IAPS