In many auction literature studying bidders' bidding strategies,it is assumed that the bidders are either risk-neutral or risk-averse.However,there may exist three risk types of bidders(risk neutral,risk averser,and risk seeking) simultaneously in real world bidding.In this paper,we assume that there exist three risk types of bidders whose attitudes toward risk are measured by "the risk indicator" and we derive the bidders' equilibrium bidding strategies under the first-price sealed-bid auction,...