Weakly normal subgroup

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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]
This is a variation of normality|Find other variations of normality | Read a survey article on varying normality


Symbol-free definition

A subgroup of a group is termed weakly normal if whenever any conjugate of it is contained in its normalizer, the conjugate is actually contained in the subgroup itself. Equivalently, a subgroup is weakly normal if it is a weakly closed subgroup inside its normalizer relative to the whole group.

Definition with symbols

A subgroup H of a group G is termed weakly normal if for any g in G, if H^g \le N_G(H) implies H^g \le H.

(Here H^g = g^{-1}Hg denotes the conjugate of H by g under the right action. We can use either the left or the right action for the definition).

Relation with other properties

Stronger properties

Weaker 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

If H \le K \le G are groups and H is weakly normal in G, then H is weakly normal in K. For full proof, refer: Weak normality satisfies intermediate subgroup condition