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: For all x_7, if x_7 were a poet, then x_7 is not a carpenter. If Patricia were a server, then Barbara is a poet. For all x_7, x_7 is a carpenter.
For all x_7, x_7 is not a poet can be inferred via the universal modus tollens rule.