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: If it is overcast, then Elisabeth is playing a game. Robert is not running. Robert is running if and only if Elisabeth is playing a game. It is not overcast if and only if Joseph is a mechanic.
If Robert goes running, then Elisabeth is playing a game can be inferred via the biconditional elimination rule. If it is not overcast, then Joseph is a mechanic can be inferred via the biconditional elimination rule. If Elisabeth plays a game, then Robert is running can be inferred via the biconditional elimination rule. If Joseph were a mechanic, then it is not overcast can be inferred via the biconditional elimination rule. Elisabeth is not playing a game can be inferred via the biconditional elimination rule.