Subset-conjugacy-closed subgroup
BEWARE! This term is nonstandard and is being used locally within the wiki. [SHOW MORE]
This article defines a subgroup property: a property that can be evaluated to true/false given a group and a subgroup thereof, invariant under subgroup equivalence. View a complete list of subgroup properties[SHOW MORE]
Definition
Definition with symbols
A subgroup of a group is termed subset-conjugacy-closed in if it satisfies the following equivalent conditions:
- For any subsets of , such that there exists with , there exists such that for all .
- is a subset-conjugacy-determined subgroup of itself with respect to , i.e., the fusion for subsets of in , is contained in .
- possesses a distinguished set of coset representatives in : In other words, there is a set of left coset representatives of in such that for all .
Equivalence of definitions
Further information: Equivalence of definitions of subset-conjugacy-closed subgroup
Relation with other properties
Stronger properties
Property | Meaning | Proof of implication | Proof of strictness (reverse implication failure) | Intermediate notions |
---|---|---|---|---|
Central factor | product with its centralizer equals whole group | central factor implies subset-conjugacy-closed | subset-conjugacy-closed not implies central factor | |FULL LIST, MORE INFO |
Retract | has a normal complement; equivalently, image of a retraction | retract implies subset-conjugacy-closed | subset-conjugacy-closed not implies retract | |FULL LIST, MORE INFO |
Direct factor | factor in an internal direct product | (via retract, via central factor) | (via retract, via central factor) | |FULL LIST, MORE INFO |
Central subgroup | contained in the center | (via central factor) | (via central factor) | |FULL LIST, MORE INFO |
Abelian abnormal subgroup | abelian and an abnormal subgroup | Abelian and abnormal implies subset-conjugacy-closed |
Weaker properties
Property | Meaning | Proof of implication | Proof of strictness (reverse implication failure) | Intermediate notions |
---|---|---|---|---|
Weak subset-conjugacy-closed subgroup | any two subsets conjugate in whole group are conjugate in subgroup; however, the conjugating element in the subgroup may not act the same element-wise | |||
Conjugacy-closed subgroup | any two elements of subgroup conjugate in whole group are conjugate in subgroup | conjugacy-closed not implies subset-conjugacy-closed | |FULL LIST, MORE INFO | |
Central factor of normalizer | a central factor of its normalizer | subset-conjugacy-closed implies central factor of normalizer | central factor of normalizer not implies subset-conjugacy-closed | |FULL LIST, MORE INFO |
SCDIN-subgroup | subset-conjugacy-determined subgroup in normalizer |
Metaproperties
Trimness
This subgroup property is trim -- it is both trivially true (true for the trivial subgroup) and identity-true (true for a group as a subgroup of itself).
View other trim subgroup properties | View other trivially true subgroup properties | View other identity-true subgroup properties
Transitivity
This subgroup property is transitive: a subgroup with this property in a subgroup with this property, also has this property in the whole group.
ABOUT THIS PROPERTY: View variations of this property that are transitive | View variations of this property that are not transitive
ABOUT TRANSITIVITY: View a complete list of transitive subgroup properties|View a complete list of facts related to transitivity of subgroup properties |Read a survey article on proving transitivity
Intermediate subgroup condition
YES: This subgroup property satisfies the intermediate subgroup condition: if a subgroup has the property in the whole group, it has the property in every intermediate subgroup.
ABOUT THIS PROPERTY: View variations of this property satisfying intermediate subgroup condition | View variations of this property not satisfying intermediate subgroup condition
ABOUT INTERMEDIATE SUBROUP CONDITION:View all properties satisfying intermediate subgroup condition | View facts about intermediate subgroup condition