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 carpenter if and only if y is a bartender. If Linda were a janitor, then Barbara is a carpenter. If Linda were not a janitor, then Mary is happy. Barbara is not a bartender.
For all y, if y were a carpenter, then y is a bartender. For all y, if y were a bartender, then y is a carpenter.