theorem Th24:
  for i,j st i in Seg n & j in Seg n holds Minor(M,i,j) = Minor(M@ ,j,i)
proof
  let i,j such that
A1: i in Seg n and
A2: j in Seg n;
  thus Minor(M,i,j) = Det Delete(M,i,j)@ by MATRIXR2:43
    .= Minor(M@,j,i) by A1,A2,Th14;
end;
