What is the correct way to show the Passive Perfect Infinitive in a textbook?

Question

I have come across the Passive Perfect Infinitive and my current textbook represents it as a nomative participle + esse (e.g. salutatus esse). However on the internet I mostly see it represented as an accusative participle + esse.

As far as I know you can theoretically use the passive perfect infinitive with every participle form although most will feel awkward and be very rare.

The most common form I have encountered is a participle accusative + esse which is generally translated as an Accusativus cum infinitvo although I realise Nominative cum infinitivo's also exist.

So now my question is, how should it be represented in a textbook? Wikitionary gives the accusative, my own textbook give it as a nominative. It would most commonly appear as an accusative but obviously in it's 'original form' it would appear as a nominative.

So if I were to write a textbook, how should I show it as? Nominative because it is the original, or the accusative because it is the most common?

Answer 1

Both are fine. I think this is analogous to the question whether a verb should be listed as trahere or traho. Both conventions are in use and both make sense; see e.g. this question for a further discussion.

The choice of the basic form of something for listing purposes is arbitrary, as it is a description in isolation of something that can only really be used in a context. Sometimes the choice is more clear, like the choice of the singular nominative for nouns. But sometimes it is further from clear, and in the case of passive perfect infinitives both nominative and accusative forms of the participle make sense. Perhaps the most typical use is with the accusative, but perhaps the nominative is somehow more fundamental.

If you write a textbook, make any choice and be consistent with it. And please do discuss the choice explicitly, lest your readers think that your choice is the only possible one.