the PET is a former.
sent1: that the PET is not a kind of a former is not false if the waterway is not a drawknife but it is anthropogenetic. sent2: the waterway is not former but it is anthropogenetic. sent3: everything is not a drawknife and it is anthropogenetic.
sent3 -> int1: the waterway is not a drawknife and is anthropogenetic.; sent1 & int1 -> hypothesis;
$hypothesis$ = the PET is a former. ; $context$ = sent1: that the PET is not a kind of a former is not false if the waterway is not a drawknife but it is anthropogenetic. sent2: the waterway is not former but it is anthropogenetic. sent3: everything is not a drawknife and it is anthropogenetic. ; $proof$ = 
sent3 -> int1: the waterway is not a drawknife and is anthropogenetic.; sent1 & int1 -> hypothesis; __DISPROVED__