Low-rank Kronecker-product approximation to multi-dimensional nonlocal operators II. HKT representation of certain operators (Q817040)

[For part I see ibid. 76, No.~3--4, 177--202 (2006; reviewed above).] The authors study the hierarchical Kronecker tensor product (HKT) representation of certain operators for low rank Kronecker product approximation to multi dimensional nonlocal operators. They apply H-matrix techniques combined with the Kronecker tensor product approximation to represent integral operators as well as of a discrete elliptic operator in a hypercube. They outline the main ideas how to construct the HKT approximations of the operator valued functions of the discrete elliptic operators with separable coefficients. In addition HKT representations of the multi-dimensional integral operators are given and an HKT approximation to the matrix valued function sign(\(A\)) of the operator \(A\) is addressed.