J.P.C.Greenlees 
``Algebraic groups and equivariant cohomology theories.'' 

We discuss a number of examples in which an equivariant 
cohomology theory is associated to an algebraic group. 
The archetype is that S1-equivariant K theory is associated 
to the multiplicative group. Slightly less familiar is the 
fact that one may associate an S1-equivariant cohomology 
to an elliptic curve over a field of characteristic zero 
(see Rational S1-equivariant elliptic cohomology). The 
features of this association are described and we speculate 
about higher dimensional examples.