Completely-S matrix

A Completely-S matrix is a type of structured matrix used in the field of numerical linear algebra and matrix theory. The term "Completely-S" typically refers to a matrix that satisfies particular properties regarding its submatrices or its structure. To clarify, the "S" in "Completely-S" usually stands for a specific property or class of matrices (like symmetric, skew-symmetric, etc.), but the exact definition can vary depending on the specific context or application.