theorem Th62:
  nf 1_FreeProduct(H) = {}
proof
  set p = <*>FreeAtoms(H);
  1_FreeProduct(H) = Class(EqCl ReductionRel H,p) by Th45;
  hence nf 1_FreeProduct(H) = nf(p,ReductionRel H) by Th59
    .= {} by Th37, MSAFREE4:17;
end;
