1. Short exchange of futures, also called short exchange, refers to short opening and short closing: short opening means selling, and short closing means buying. Empty orders exchange itself does not increase or decrease positions, because empty orders are changed from one person's hand to another's.

2. futures overpayment is also called overpayment. When buying and selling positions, it means that one person gives up one hand and is bought by another. This is called multivariate exchange.