An Analytical and Applied Study on the Summation Properties of Σ- Strictly Diagonally Dominant Matrices with Numerical Verification
Keywords:
k-subdirect sum, H-matrices, Σ-SDD matrices, overlapping blocks, diagonal dominanceAbstract
In this research, we extend the existing results on subdirect sums of S-strictly diagonally dominant matrices to the more general class of Σ-Strictly Diagonally Dominant (Σ-SDD) matrices. As Σ-SDD matrices form a proper superclass of S-SDD matrices and a subclass of H-matrices, we investigate their structural properties under matrix combination operations. Specifically, we provide a complete characterization of the conditions under which the k-subdirect sum of two Σ-SDD matrices preserves the Σ-SDD property. Furthermore, we establish when the conventional sum of two Σ-SDD matrices remains Σ-SDD. These results broaden the understanding of diagonal dominance under scaling and contribute to the study of matrix stability within hierarchical subclasses of H-matrices.
