T*-group: Difference between revisions

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


A [[group]] is said to be a T*-group if every subgroup of it is a [[T-group]], that is, if a subgroup is subnormal in some intermediate subgroup, it is also normal in that intermediate subgroup.
A [[group]] is said to be a T*-group if it satisfies the following equivalent conditions:
 
* Every subgroup of it is a [[defining ingredient::T-group]]
* If a subgroup is subnormal in some intermediate subgroup, it is also normal in that intermediate subgroup.
* Every subgroup of it is an [[defining ingredient::intermediately subnormal-to-normal subgroup]].


===Definition with symbols===
===Definition with symbols===
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===Stronger properties===
===Stronger properties===


* [[Abelian group]]
* [[Weaker than::Abelian group]]
* [[Dedekind group]]
* [[Weaker than::Dedekind group]]
* [[Weaker than::Group in which every subgroup is pronormal]]


===Weaker properties===
===Weaker properties===


* [[T-group]]
* [[Stronger than::T-group]]
* [[HN*-group]] (when we are working with [[finite group]]s)
* [[Stronger than::HN*-group]]
* [[HN-group]] (when we are working with [[finite group]]s)
* [[Stronger than::HN-group]]


==Metaproperties==
==Metaproperties==

Latest revision as of 00:36, 22 February 2009

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
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This article is about a definition in group theory that is standard among the group theory community (or sub-community that dabbles in such things) but is not very basic or common for people outside.
VIEW: Definitions built on this | Facts about this: (facts closely related to T*-group, all facts related to T*-group) |Survey articles about this | Survey articles about definitions built on this
VIEW RELATED: Analogues of this | Variations of this | Opposites of this |
View a list of other standard non-basic definitions

Definition

Symbol-free definition

A group is said to be a T*-group if it satisfies the following equivalent conditions:

Definition with symbols

A group is said to be a T*-group if whenever , we have . In other words, any subgroup of is a T-group.

Relation with other properties

Stronger properties

Weaker properties

Metaproperties

Subgroups

This group property is subgroup-closed, viz., any subgroup of a group satisfying the property also satisfies the property
View a complete list of subgroup-closed group properties

Any subgroup of a T*-group is a T*-group. This follows from the definition.

Quotients

This group property is quotient-closed, viz., any quotient of a group satisfying the property also has the property
View a complete list of quotient-closed group properties