Have you tried turning the general statement around to a negative statement? That way it becomes a search for counterexamples. Of course, if this fails it could just be because you’re forgetting, but it seems to me that attempting to construct a counterexample would help jog the memory.
Have you tried turning the general statement around to a negative statement? That way it becomes a search for counterexamples. Of course, if this fails it could just be because you’re forgetting, but it seems to me that attempting to construct a counterexample would help jog the memory.