摘要

This work is concerned with estimating the lower bound of rank for a given quaternion square matrix, rectangular matrix or normal matrix, and estimating the upper bound for the sum of the eigenvalue norms of a given quaternion matrix. A sufficient condition is provided to confirm whether a given quaternion matrix is nonsingular. It sharpens some results due to Tu Bo-xun and Semyon Aranovich Gerschgorin and Schur, respectively. Some examples are provided to show the effectiveness of our results.