What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: Charles is playing squash. It is snowing if and only if Richard is listening to a song. Richard is listening to a song if and only if Jennifer is poor. Jennifer is not poor.
Charles is playing squash and Jennifer is not poor can be inferred via the conjunction rule. Jennifer is not poor and Charles is playing squash can be inferred via the conjunction rule. If it snows, then Richard is listening to a song can be inferred via the biconditional elimination rule. If Richard listens to a song, then Jennifer is poor can be inferred via the biconditional elimination rule. If Richard listens to a song, then it is snowing can be inferred via the biconditional elimination rule. If Jennifer were poor, then Richard is listening to a song can be inferred via the biconditional elimination rule. Richard is not listening to a song can be inferred via the biconditional elimination rule.