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: For all x_10, if x_10 plays squash, then x_10 is playing a game. John is a politician if and only if David is playing squash. David is not playing a game.
If John were a politician, then David is playing squash can be inferred via the biconditional elimination rule. If David plays squash, then John is a politician can be inferred via the biconditional elimination rule.