homogeneous group
A homogeneous group is a set together with a map satisfying:
i)
ii)
iii)
for all .
A map of homogeneous groups is a homomorphism if it , for all .
A non-empty homogeneous group is essentially a group, as given any , we may define the following product on :
.
This gives the of a group with identity . The choice of does not affect the isomorphism class of the group obtained.
One may recover a homogeneous group from a group obtained this way, by setting
.
Also, every group may be obtained from a homogeneous group.
Homogeneous groups are homogeneous: Given we have a homomorphism taking to , given by .
In this way homogeneous groups differ from groups, as whilst often used to describe symmetry, groups themselves have a distinct element: the identity.
Also the definition of homogeneous groups is given purely in of identities, and does not exclude the empty set.