reserve A,B for Ordinal,
        o for object,
        x,y,z for Surreal,
        n for Nat,
        r,r1,r2 for Real;

theorem Th105:
  dom name-r x = name-ord x = dom name-y x
proof
  dom name-r x = dom name-y x & Sum(name-r x,name-y x)==x by Def23;
  hence thesis by Th104;
end;
