Extensible automorphism

You might be looking for:


 * extensible equals inner: A proof that every extensible automorphism of a group is an inner automorphism. An automorphism $$\sigma$$ of a group $$G$$ is termed extensible if for any group $$H$$ containing $$G$$, there exists an automorphism $$\sigma'$$ of $$H$$ whose restriction to $$G$$ equals $$\sigma$$.
 * extensible automorphisms problem: A discussion of extensibility of automorphisms and related questions.
 * group property-conditionally extensible automorphism: The property of an automorphism being extensible with respect to a group property.
 * variety-extensible automorphism: extensibility with respect to a variety of algebras.

Also check out quotient-pullbackable automorphism.