theorem
  H is disjunctive implies H = (the_left_argument_of H) 'or'
  the_right_argument_of H
proof
  assume
A1: H is disjunctive;
  then ex F1 st H = (the_left_argument_of H) 'or' F1 by Th39;
  hence thesis by A1,Th39;
end;
