of two groups G and H with group operations ρ and τ respectively. The group consisting of the elements in the Cartesian product of G and H and on which there is a dyadic operation ∘ defined as follows:
The identity of this group is then just (
eG,
eH), where
eG and
eH are the identities of groups
G and
H respectively. The inverse of (
g,
h) is then (
g−1,
h−1).
These concepts can be generalized to deal with the direct product of any finite number of groups on which there are specified group operations.