# Subgroup

In group theory, a branch of mathematics, given a group ${\displaystyle G}$ under a binary operation, a subset ${\displaystyle H}$ of ${\displaystyle G}$ is called a subgroup of ${\displaystyle G}$ if the elements ${\displaystyle H}$ also forms a group under the binary operation.

The situation could arise in which the subset ${\displaystyle H}$ does not comply with the binary operation.