What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is not late. If Thomas were a mechanic, then it is late. For all y, y is a mechanic if and only if y is a carpenter.
Thomas is not a mechanic. For all y, if y were a mechanic, then y is a carpenter. For all y, if y were a carpenter, then y is a mechanic.