My mistake, I misunderstood what “absolute superlative” means. I retract my earlier statement.
I found an enfusiastic “bella, bella!” got the message accross when on holiday in Italy, though whether that would seem strange if I were not obviously a tourist I don’t lnow.
It applies to all past participles, which have to agree in the same way adjectives do. In the case of composite tenses using the participle, when the compound is formed with essere, the past participle has to agree with the subject, e.g. L’ora era venuta (the hour had come). Capisci?
But conjugations with avere do not make the participle agree with the subject.
Although, depending on the sentence construction, the participle conjugated with avere may have to agree with the direct object, e.g. Dove sono andate le verdure? Le ho mangiate tutte. (Where’d the vegetables go? I ate 'em all.)
To take your example, sorry, hai vista doesn’t mean ‘have you seen’, it means ‘you have a view’, in which vista can only be parsed as a noun. To make it a verb conjugation, you’d have to say “hai visto [direct object]” regardless of gender. Even if the speaker is female.
Reflexive verbs are always conjugated with essere for the past participle, which always agrees with the subject as to gender and number. So I would say Mi sono vista (I saw myself) because I’m a woman, while a man would say Mi sono visto.
Phew, time to go back to the books. I’ve never taken a class but I studied out of books profusely to prepare for a business trip to Italy, and then loved it so much I’ve been back three more times. I hope to go to Florence this summer, so I’d better get to work!
Bellissimo. Contact me privately, vicino, I’ll help you practice Italian before you go. (I need the practice too.)