If the appointment of the sole arbitrator (here by the Chairman of the AC pursuant to Section 21(4) of the Domestic Rules) is contingent on a condition that the parties fail to agree on the sole arbitrator, then it is necessary to examine whether the parties had attempted to conclude such agreement. If the claimant refused to conclude the agreement on the sole arbitrator in the arbitral proceedings, then it is necessary to examine the claimant’s refusal. In proceedings for annulment of an arbitral award pursuant to Section 31(c) of the ArbAct [CZE], as a question of fact the court examines whether one of the parties refused to agree on the arbitrator. It shall not suffice if the claimant (claimant in the arbitral proceedings, i.e. respondent in the proceedings for annulment of arbitral award), merely resigns on the agreement regarding the sole arbitrator by commencing proceedings with an arbitral tribunal.