the checkering does not occur and the revenging Gibson does not occur.
sent1: that the checker does not occur and the revenging Gibson does not occur is wrong.
sent1 -> hypothesis;
$hypothesis$ = the checkering does not occur and the revenging Gibson does not occur. ; $context$ = sent1: that the checker does not occur and the revenging Gibson does not occur is wrong. ; $proof$ = 
sent1 -> hypothesis; __DISPROVED__