Rule reminder
'Per + infinitive' expresses cause when BOTH clauses share the same subject. The infinitive is present for simultaneous actions, past (infinito passato: aver fatto) for prior actions. It is more concise than a full causal clause. Example: 'È stato punito per aver mentito' = 'He was punished for having lied.'
When is 'infinito passato' (per aver fatto) required instead of 'infinito presente' (per fare)?