Trivial group: Difference between revisions
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The '''trivial group''' is the group with only one element, which is its identity element. | The '''trivial group''' is the group with only one element, which is its identity element. | ||
===Alternative definitions=== | |||
* The {{cyclic group}} on one element | |||
* The {{symmetric group}} on one element | |||
* The {{projective general linear group}} of order 1 over any field | |||
* The {{special linear group}} of order 1 over any field | |||
==Importance== | ==Importance== |
Revision as of 23:58, 23 September 2007
This article is about a particular group, i.e., a group unique upto isomorphism. View specific information (such as linear representation theory, subgroup structure) about this group
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Definition
The trivial group is the group with only one element, which is its identity element.
Alternative definitions
- The cyclic group on one element
- The symmetric group on one element
- The projective general linear group of order 1 over any field
- The special linear group of order 1 over any field
Importance
The trivial group is important in the following ways:
- For any group, there is a unique homomorphism from the trivial group to that group, namely the homomorphism sending it to the identity element. Thus, the trivial group occurs in a unique way as a subgroup for any given group, namely the one-element subgroup comprising the identity element. This is termed the trivial subgroup.
- For any group, there is a unique homomorphism to the trivial group from that group, namely the homomorphism sending everything to the identity element. Thus, the trivial group occurs in a unique way as a quotient group of any given group, namely its quotient by itself. This is termed the trivial quotient.