What are all the matrices that commute wit a matrix of ones?

Jamin2112 · Mar 2, 2013

Homework Statement

What are the characteristics of a matrix that commutes with a matrix of ones?

None.

I'm helping a buddy with his homework and I can't figure out this problem.

jbunniii · Mar 2, 2013

Try working it out explicitly for a 2x2 matrix (it's easy) and see if you can generalize from there.

Simon Bridge · Mar 2, 2013

Relevant equations None.

What about the definition of "commute"?

Jamin2112 · Mar 3, 2013

Figured out the answer, I think. The sum of every row and column is the same.

Dick · Mar 4, 2013

Jamin2112 said:

Figured out the answer, I think. The sum of every row and column is the same.

Sounds right, can you prove it?

Jamin2112 · Mar 4, 2013

Dick said:

Sounds right, can you prove it?

Yes, but the problem doesn't ask me to

Dick · Mar 4, 2013

Jamin2112 said:

Yes, but the problem doesn't ask me to

Fair enough.