there is something such that if it is reducible it is not an ultimatum and it is a pteridophyte.
sent1: the fact that the muzhik is not an ultimatum but it is a pteridophyte is not false if it is reducible. sent2: there is something such that if it is reducible it is an ultimatum that is a pteridophyte. sent3: there exists something such that if it is a vicegerent it is a greenmail.
sent1 -> hypothesis;
$hypothesis$ = there is something such that if it is reducible it is not an ultimatum and it is a pteridophyte. ; $context$ = sent1: the fact that the muzhik is not an ultimatum but it is a pteridophyte is not false if it is reducible. sent2: there is something such that if it is reducible it is an ultimatum that is a pteridophyte. sent3: there exists something such that if it is a vicegerent it is a greenmail. ; $proof$ = 
sent1 -> hypothesis; __PROVED__