Refers to the compound arbitrage strategy that adopts the bull spread strategy and the bear spread strategy, including the long butterfly spread strategy and the short butterfly spread strategy. The long butterfly spread strategy refers to buying a call option with a lower exercise price and a call option with a higher exercise price, and selling two call options with exercise prices between the two. The short butterfly spread strategy refers to selling a call option with a lower exercise price and a call option with a higher exercise price, and buying two call options with exercise prices between the two.