%0 Journal Article %T Riesz measures and Wishart laws associated to quadratic maps %A Piotr Graczyk %A Ishi Hideyuki %J Statistics %D 2011 %I arXiv %X We introduce a natural definition of Riesz measures and Wishart laws associated to an $\Omega$-positive (virtual) quadratic map, where $\Omega \subset \real^n$ is a regular open convex cone. We give a general formula for moments of the Wishart laws. Moreover, if the quadratic map has an equivariance property under the action of a linear group acting on the cone $\Omega$ transitively, then the associated Riesz measure and Wishart law are described explicitly by making use of theory of relatively invariant distributions on homogeneous cones. %U http://arxiv.org/abs/1107.0147v1