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

theorem Th54:
  for f1,f2 being Morphism of EmptyMS C,a holds f1 = f2
proof
  let f1,f2 be Morphism of EmptyMS C,a;
  EmptyMS C is initial by Def26;
  then consider f being Morphism of EmptyMS C,a such that
A1: for g being Morphism of EmptyMS C, a holds f = g;
  thus f1 = f by A1
    .= f2 by A1;
end;
