If a finite group G is isomorphic to a subgroup of SO(3), then G has
the D2-property. Let X be a finite complex satisfying Wall's D2-conditions.
If π1(X)=G is finite, and χ(X)≥1−Def(G), then X∨S2 is
simple homotopy equivalent to a finite 2-complex, whose simple homotopy type
depends only on G and χ(X).Comment: 9 page