let n be Nat; :: thesis: for M1, M2 being Matrix of n,REAL holds
( len M1 = len M2 & width M1 = width M2 )
let M1, M2 be Matrix of n,REAL; :: thesis: ( len M1 = len M2 & width M1 = width M2 )
( width M1 = n & len M1 = n ) by MATRIX_0:24;
hence ( len M1 = len M2 & width M1 = width M2 ) by MATRIX_0:24; :: thesis: verum