Key legal question
Whether the complaint could be entertained on behalf of the heirs other than P. X.
Extracted holding
No. The other heirs had waived continuation of the cantonal appeal, which implied withdrawal of authority to pursue the federal proceeding; no new authority was shown.
Extracted reasoning
Their declaration accepting the first-instance judgment and renouncing continuation amounted to revocation of the power of attorney for further litigation. Only P. X.'s mandate covered the federal complaint.