reserve Y for non empty set;
reserve Y for non empty set;
reserve Y for non empty set;
reserve Y for non empty set,
  a,b,c,d,e,f,g for Function of Y,BOOLEAN;

theorem Th38a:
  a '<' a 'or' b
proof
  a 'imp' (a 'or' b) = I_el Y by Th26;
  hence thesis by BVFUNC_1:16;
end;
