对于这个问题而言Sylvester不等式甚至是取等号的.
事实上利用初等变换
R(A) + R(A-E)
= R [A 0; 0 A-E]
= R [A 0; A A-E]
= R [A -A; A -E]
= R [A-A^2 -A; 0 -E]
= R [0 0; 0 E] = n
对于这个问题而言Sylvester不等式甚至是取等号的.
事实上利用初等变换
R(A) + R(A-E)
= R [A 0; 0 A-E]
= R [A 0; A A-E]
= R [A -A; A -E]
= R [A-A^2 -A; 0 -E]
= R [0 0; 0 E] = n