kvacit pāṭhaḥ pramāṇe 'bhāva iti. tatra nirdhāraṇe saptamī, jātāvekavacanam. pramāṇānāṃ madhye 'bhāvaḥ pramāṇam ity arthaḥ.
In some readings it is "pramāṇe 'bhāva". There the locative case expresses specification, [with] singular number referring to the class. The meaning is "negation is a means of valid cognition among the pramāṇas."