-matrices can be used to construct efficient approximations of discretized integral operators. The
-matrix approximation can be constructed efficiently by interpolation, Taylor or multipole expansion of the integral kernel function, but the resulting representation requires a large amount of storage.
In order to improve the efficiency, local Schur decompositions can be used to eliminate redundant functions from an original approximation, which leads to a significant reduction of storage requirements and algorithmic complexity.
AMS Subject Classifications: 45B05 - 65N38 - 65F30
Keywords Hierarchical matrices - data-sparse approximation - nested bases