# need ur help [closed]

prove that rank(A?B)?rank(A)?rank(B) where A and B are n*n matrices

need ur help [closed]

prove that rank(A?B)?rank(A)?rank(B) where A and B are n*n matrices

close date 2013-10-05 22:50:52

Asked: ** 2013-10-05 10:35:23 +0200 **

Seen: **355 times**

Last updated: **Oct 05 '13**

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Again, Sage cannot *prove* such things. You can of course do `A = matrix([0]); B = matrix([1]); rank(A)*rank(B) == rank(A*B)` to get `True` but that is not a proof.