Kernrechtsfrage
Whether the rent-default termination under Art. 257d OR was valid despite the tenants' set-off objection.
Extrahierter Entscheid
The set-off claim was insufficiently substantiated and, in any event, the evidence offered could not establish it; the termination for arrears was therefore valid.
Extrahierte Begründung
The tenants did not specify the work allegedly performed with sufficient detail, so no evidence had to be taken. The appellate court's alternative anticipatory assessment of the evidence was not shown to be arbitrary.