delete imnotOLD (it's time to admit I am): the proof has no advantage whatsoever over imnot, and eventhough it has been obsolete for less than a year, I was the person adding it (crediting Mario Carneiro), so I feel that I can remove it
delete imnotOLD (it's time to admit I am): the proof has no advantage whatsoever over imnot, and eventhough it has been obsolete for less than a year, I was the person adding it (crediting Mario Carneiro), so I feel that I can remove it

metamath/set.mm,metamath/set.mm,metamath/set.mm