What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one y_1 for which if y_1 were excited, then y_1 is a carpenter. For all y_1, if y_1 were a carpenter, then y_1 is excited. For all y_1, if y_1 were excited, then y_1 is a carpenter.
For all y_1, y_1 is a carpenter if and only if y_1 is excited. For all y_1, y_1 is excited if and only if y_1 is a carpenter. There is at least one y_1 for which y_1 is excited if and only if y_1 is a carpenter. There is at least one y_1 for which y_1 is a carpenter if and only if y_1 is excited.