Quaternion H-type group and differential operatorΔ_λ

We study the relations between the quaternion H-type group and the boundary of the unit ball on the two-dimensional quaternionic space.The orthogonal projection of the space of square integrable functions defined on quaternion H-type group into its subspace of boundary values of q- holomorphic functions is considered.The precise form of Cauchy-Szeg(?)kernel and the orthogonal projection operator is obtained.The fundamental solution for the operatorΔ_λis found.