What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y, y is a mechanic if and only if y is an office clerk. For all y, if y were an office clerk, then y is a mechanic. For all y, if y were a mechanic, then y is an office clerk.
For all y, y is an office clerk if and only if y is a mechanic. For all y, y is a mechanic if and only if y is an office clerk. For all y, if y were a mechanic, then y is an office clerk. For all y, if y were an office clerk, then y is a mechanic.