# 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 15:50:52

Asked: **
2013-10-05 03:35:23 -0600
**

Seen: **35 times**

Last updated: **Oct 05 '13**

Matrices not equal, but entries are. Why?

Substitution using Dictionary with Matrix as Value

problems with product of vector of symbols with square matrix

checking if a subset of columns of a matrix span a given vector

all final(optimal) values of for loop

elementary matrices for elementary row operations

Generating random normal vectors and matrices

How to efficiently test whether a matrix can be written as a certain type of word

Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.

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.