The equivariant Grothendieck groups of the Russell-Koras threefolds

The Russell-Koras contractible threefolds are the smooth affine threefolds having a hyperbolic C*-action with quotient isomorphic to the corresponding quotient of the linear action on the tangent space at the unique fixed Fei nt. Koras and Russell gave a concrete description of all such threefolds an d determined many interesting properties they possess. We use this descript ion and these properties to compute the equivariant Grothendieck groups of these threefolds. In addition, we give certain equivariant invariants of th ese rings.