On a Test Question of Advanced Algebra
Dai Pei-pei · Journal of Putian University · 2006
In this paper,we discuss a test question about the sum of the ranks of matrices A and A + E which is presented in the web of the national grade excellent course in 2004——the course of advanced algebra in Jilin university.We point out that the answer to the test question is not unique.Then we obtain the upper and lower bounds of the sum,and present the necessary and sufficient conditions for letting the upper and lower bounds hold respectively.Furthermore,we generalize the results.