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: Richard is an office clerk if and only if it is snowing. John is a writer if and only if it is snowing. Richard is not an office clerk. For all x_7, x_7 is a bartender if and only if x_7 is a writer.
If Richard were an office clerk, then it is snowing can be inferred via the biconditional elimination rule. If John were a writer, then it is snowing can be inferred via the biconditional elimination rule. If it snows, then Richard is an office clerk can be inferred via the biconditional elimination rule. If it snows, then John is a writer can be inferred via the biconditional elimination rule. It is not snowing can be inferred via the biconditional elimination rule. For all x_7, if x_7 were a bartender, then x_7 is a writer can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 were a writer, then x_7 is a bartender can be inferred via the universal biconditional elimination rule.