  For any rational homology 3-sphere and one of its spin^{c}-structures,
Ozsvath and Szabo defined a topological invariant, called d-invariant. Given a
knot in the 3-sphere, the d-invariants associated with the prime-power-fold
branched covers of the knot, obstruct the smooth sliceness of the knot. These
invariants bear some structural resemblances to Casson-Gordon invariants, which
obstruct the topological sliceness of a knot. Se-Goo Kim found a polynomial
splitting property for Casson-Gordon invariants. In this paper, we show a
similar result for Ozsvath and Szabo's d-invariants. We give an application of
the result.
