Show that a set of matrices is a ring without an identity element. - I am given the set of infinite-by-infinite matrices with real entries that have only finitely many nonzero entries. Also, the matrix has entries a_ij, where i and j are natural numbers and there is a ...
Matrices - I need to understand how to work this problem
1. What must be true about x, y, z and w if AB = BA for the matrices
(see problem as an attachment)