Questão jurídica principal
Whether the constitutional appeal against the cantonal decision reviewing the arbitral award was admissible and properly exhausted.
Decisão extraída
The main request for reform was inadmissible because only cassatory relief was available, and the new restitution claim had not been raised below.
Fundamentação extraída
In a challenge under the Concordat on arbitration, the federal appeal is limited to the cantonal last-instance decision and is only cassatory; new claims are barred.