Tuesday, 21 May 2013

linear algebra - Do elementary row operations give a similar matrix transformation?



So we define two matrices A,B to be similar if there exists an invertible square matrix P such that AP=PB. I was wondering if A,B are related via elementary row operations (say, they are connected via some permutation rows for example) then are the necessarily similar?




Obviously swapping rows multiplies the determinant by 1 but I was thinking if we permute rows in pairs, would this allow us to construct a similarity transformation?


Answer



Every invertible matrix is equivalent via row operations to the identity matrix, and the identity matrix is only similar to itself.



This also gives a counterexample to the permutation question; the identity matrix is not similar to a non-identity permutation matrix.


No comments:

Post a Comment

real analysis - How to find limhrightarrow0fracsin(ha)h

How to find lim without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...