Constructor for matrices. The arguments are a list of rows in the matrix.
(Undefined (Arity Matrix-Of-Rows))
(<=> (= (Matrix-Of-Rows @Elements) ?M)
(And (Matrix ?M)
(= (Row-Dimension ?M) (Length (Listof @Elements)))
(= (Row ?I ?M) (Nth (Listof @Elements) ?I))
(=> (And (Item ?E1 (Listof @Elements))
(Item ?E2 (Listof @Elements)))
(= (Column-Dimension ?E1) (Column-Dimension ?E2)))))