Question juridique clé
Whether the appeal was admissible despite the absence of a valid power of attorney for the federal proceedings
Solution extraite
The appeal could not be considered because the deficiency was not cured within the deadline set by the court.
Motifs extraits
Party representatives before the Federal Supreme Court must prove their authority. When the power of attorney is missing, a reasonable cure period must be granted with the warning that the filing will otherwise be disregarded. Here, the submitted substitute power of attorney was limited to proceedings before the cantonal tax court, and no valid federal power of attorney was filed in time.