theorem
  for F be finite Subset of LTLB_WFF holds (F |-0 'G' A implies F |- A)
proof
  let F be finite Subset of LTLB_WFF;
  assume F |-0 'G' A; then
  F |=0 'G' A by th266;
  hence F |- A by LTLAXIO4:33,th21;
end;
