Normaliser
Jump to navigation
Jump to search

In group theory, the normaliser of a subgroup of a group (mathematics) is the set of all group elements which map the given subgroup to itself by conjugation.
Formally, for H a subgroup of a group G, we define
A subgroup of G is normal in G if its normaliser is the whole of G.
The normaliser of the trivial subgroup is the whole group G.