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: Robert is sleeping if and only if John is a sailor. John is not a sailor. Robert is sleeping or it is cloudy.
If Robert sleeps, then John is a sailor can be inferred via the biconditional elimination rule. If John were a sailor, then Robert is sleeping can be inferred via the biconditional elimination rule. Robert is not sleeping can be inferred via the biconditional elimination rule.