ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Sat, 05 Oct 2013 22:50:47 +0200need ur helphttps://ask.sagemath.org/question/7529/need-ur-help/prove that rank(A?B)?rank(A)?rank(B) where A and B are n*n matricesSat, 05 Oct 2013 10:35:23 +0200https://ask.sagemath.org/question/7529/need-ur-help/Comment by kcrisman for <p>prove that rank(A?B)?rank(A)?rank(B) where A and B are n*n matrices</p>
https://ask.sagemath.org/question/7529/need-ur-help/?comment=16955#post-id-16955Again, 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.Sat, 05 Oct 2013 22:50:47 +0200https://ask.sagemath.org/question/7529/need-ur-help/?comment=16955#post-id-16955