homogeneous group
A homogeneous group is a set G together with a map ():G×G×G→G satisfying:
i)(a,a,b)=b
ii)(a,b,b)=a
iii)((a,b,c),d,e)=(a,b,(c,d,e))
for all a,b,c,d,e∈G.
A map f:G→H of homogeneous groups is a homomorphism if it f(a,b,c)=(fa,fb,fc), for all a,b,c∈G.
A non-empty homogeneous group is essentially a group, as given any x∈G, we may define the following product on G:
ab=(a,x,b).
This gives G the of a group with identity x. The choice of x does not affect the isomorphism class of the group obtained.
One may recover a homogeneous group from a group obtained this way, by setting
(a,b,c)=ab-1c.
Also, every group may be obtained from a homogeneous group.
Homogeneous groups are homogeneous: Given a,b∈G we have a homomorphism f taking a to b, given by fx=(x,a,b).
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.
Title | homogeneous group |
---|---|
Canonical name | HomogeneousGroup |
Date of creation | 2013-03-22 16:12:12 |
Last modified on | 2013-03-22 16:12:12 |
Owner | whm22 (2009) |
Last modified by | whm22 (2009) |
Numerical id | 15 |
Author | whm22 (2009) |
Entry type | Definition |
Classification | msc 20A05 |
Defines | homomorphism of homogeneous groups |