A 2-complex is collapsible if and only if it admits a strongly convex metric
Let be a topological group. We give the existence of an equivariant homology and cohomology theory, defined on the category of all -pairs and -maps, which both satisfy all seven equivariant Eilenberg-Steenrod axioms and have a given covariant and contravariant, respectively, coefficient system as coefficients.In the case that is a compact Lie group we also define equivariant -complexes and mention some of their basic properties.The paper is a short abstract and contains no proofs.