  Recently, the Fischer decomposition for polynomials on superspace R^{m|2n}
(that is, polynomials in m commuting and 2n anti-commuting variables) has been
obtained unless the superdimension M=m-2n is even and non-positive. In this
case, it turns out that the Fischer decomposition of polynomials into spherical
harmonics is quite analogous as in R^m and it is an irreducible decomposition
under the natural action of Lie superalgebra osp(m|2n). In this paper, we
describe explicitly the Fischer decomposition in the exceptional case when M is
even and non-positive. In particular, we show that, under the action of
osp(m|2n), the Fischer decomposition is not, in general, a decomposition into
irreducible but indecomposable pieces.
