Questione giuridica chiave
Whether the appellant could deduct all mortgage interest despite joint and several liability for part of the debt.
Decisione estratta
Only the share of interest corresponding to the portion of the debt for which he was definitively liable was deductible.
Motivazione estratta
Private interest is deductible only for debt personally and definitively owed; joint and several co-debtorship does not change the definitive economic burden because of recourse rights against the other co-debtor.