theorem :: MATRIX_0:71

for D being non empty set
for G being Matrix of D
for k, m being Nat st width G = m + 1 & m > 0 & k in Seg m holds
( Col ((DelCol (G,1)),k) = Col (G,(k + 1)) & k in Seg (width (DelCol (G,1))) & k + 1 in Seg (width G) )