theorem
  for A,B be Matrix of len b1,len b2,K st 
  Mx2Tran(A,b1,b2) = Mx2Tran(B,b1,b2) holds A = B
proof
  let A,B be Matrix of len b1,len b2,K;
  assume Mx2Tran(A,b1,b2)=Mx2Tran(B,b1,b2);
  hence A = AutMt(Mx2Tran(B,b1,b2),b1,b2) by Th36
    .= B by Th36;
end;
