I think I just realized that years now, I understand wrongly the verbs {tob} and {Daj}. But before I start, just to be on the same page (as americans say), here are the definitions:

tob (v) test conclusively, prove

Suppose I write the following sentences:

nger vItobpu'

nger vIDajpu'

Years now, I thought that the {nger vItobpu'} means "I proved that the theory is correct", and that the {nger vIDajpu'} means "I proved that the theory is wrong".

But now I realized that the meanings are rather the folllowing:

nger vItobpu'

I tested conclusively the theory

(I say that I tested it thoroughly, but without this meaning that the theory is necessarily correct; after the "testing" finished, perhaps the conclusion was that the theory was perfectly wrong)

nger vIDajpu'

I tested inconclusively the theory

(I just say that I didn't thoroughly test the theory; it may be a valid theory, or it may be a wrong one, but the "testing" wasn't thorough/effective enough to come to definite conclusion)

Is my understanding correct?

~ Dana'an