Subgroup having a left transversal that is also a right transversal
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]
Statement
Suppose is a subgroup of a group . We say that is a subgroup having a left transversal that is also a right transversal if there exists a subset of such that is a left transversal of and is also a right transversal of .
Examples
Non-examples
See subgroup need not have a left transversal that is also a right transversal for an example of a subgroup that does not satisfy this property. In the example, the whole group is isomorphic to free group:F2 and the subgroup is free on a countable generating set.
Relation with other properties
Stronger properties
Property | Meaning | Proof of implication | Proof of strictness (reverse implication failure) | Intermediate notions |
---|---|---|---|---|
Subgroup of finite group | the whole group is finite | subgroup of finite group has a left transversal that is also a right transversal | |FULL LIST, MORE INFO | |
Subgroup of finite index | the index of the subgroup in the whole group is finite | subgroup of finite index has a left transversal that is also a right transversal | |FULL LIST, MORE INFO | |
Normal subgroup | the left cosets are the same as the right cosets | every left transversal is a right transversal. Note that existence of transversals requires the axiom of choice | |FULL LIST, MORE INFO | |
Permutably complemented subgroup | has a permutable complement | we can take the permutable complement as the left transversal that is also a right transversal | |FULL LIST, MORE INFO | |
Retract | has a normal complement | (via permutably complemented, via subset-conjugacy-closed) | |FULL LIST, MORE INFO | |
Subgroup having a symmetric transversal | has a left transversal (equivalently, right transversal) that is a symmetric subset | |FULL LIST, MORE INFO | ||
Subgroup having a 1-closed transversal | has a left transversal (equivalently, right transversal) that is a 1-closed subset, i.e., a union of subgroups | |FULL LIST, MORE INFO | ||
Subgroup having a transversal comprising involutions | has a left transversal (equivalently, right transversal) all of whose non-identity elements are involutions | |FULL LIST, MORE INFO |
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
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