Assertion: auxiliary verb's form | /r/HasProperty | true perfect forms
Facets:
value: by some linguists
type: OTHER
value: by not others
type: OTHER
Source sentences:
text: This applies particularly when the perfect infinitive is used together with modal verbs: for example, he could not have been a genius might be considered (based on its meaning) to be a past tense of he cannot/could not be a genius; such forms are considered true perfect forms by some linguists but not others.