reserve o,m for set;
reserve C for Cartesian_category;
reserve a,b,c,d,e,s for Object of C;

theorem Th26:
  for f,k being Morphism of c,a, g,h being Morphism of c,b st Hom(
  c,a) <> {} & Hom(c,b) <> {} & <:f,g:> = <:k,h:> holds f = k & g = h
proof
  let f,k be Morphism of c,a, g,h be Morphism of c,b;
  assume
A1: Hom(c,a) <> {} & Hom(c,b) <> {};
  then pr1(a,b)*<:f,g:> = f & pr2(a,b)*<:f,g:> = g by Def10;
  hence thesis by A1,Def10;
end;
