Subgroup
A subset H of G that forms
a group under the group operation of G.
Subgroup Properties
2. H is nonempty and for all x,y in H, we have xy^-1 in H.
Subgroup Test
Showing the 2 subgroup properties are true.
Homomorphism
A map between 2 groups that preserves the operations of said groups.
Isomorphism
A homomorphism that is also a bijection. (1-1 and onto)
Image of Homomorphism
A subgroup of H and its kernal is a subgroup of G
Cayley’s Theorem
Every finite group G is isomorphic to a subgroup of the Symmetric group acting on G
Injective Group Homomorphism
if and only if its kernal is trivial