Before revision:  To apply ARL, we turn the well-studied single-agent model of Avellaneda and Stoikov [2008] into a discrete-time zero-sum game between a market maker and adversary , a proxy for other market participants who would like to profit at the market maker's expense.
After revision:  To apply ARL, we turn the well-studied single-agent model of Avellaneda and Stoikov [2008] into a discrete-time zero-sum game between a market maker and adversary . The adversary acts as a proxy for other market participants who would like to profit at the market maker's expense.