Consider the following premises. exists y_1: Q_2(y_1) or P(y_1). forall y_1: T(y_1) <-> Q_2(y_1). forall y_1: T(y_1) <-> P_1(y_1). forall y_1: ~P_1(y_1). Can we infer exists y_1: Q_2(y_1) or P(y_1) from them? If possible, name the inference rules being used at each step.
That is one of the premises. Therefore, the answer is yes.