Answer ... Generally, the dispute should be decided in light of the parties’ choice of law. Unless the parties have agreed otherwise, the chosen law is the substantive law of the relevant state, excluding the private international law rules thereof.
In the absence of a choice of law, the applicable substantive law is determined by the arbitration tribunal on the basis of the international private law rules that the tribunal considers applicable.
Answer ... The tribunal will adopt its decision in line with the stipulations of the contract and will take into account applicable customary practices. The content of the applicable law may be a question that requires the taking of evidence.
In addition, the tribunal may adopt a decision on the basis of equity (ex aequo et bono), provided that the parties have expressly authorised it to do so.