Dear Forum,
I have one question on matrix multiplication.
Suppose there are 2 matrices 
A = 1 1 0
0 2 1
2 0 1
B = 1
1
2
and AB = 0 (Zero Matrix)
if B not a zeromatrix, then rank(A) is less than s, where s is the dimension of B.
I wanted to have a proof and explanation for this.
Any book / link? :)
Thank You,
Raj
