What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Barbara is not a poet. Sarah is writing a letter if and only if Barbara is a poet. If Linda were fast, then Sarah is writing a letter. Jessica is a nurse.
Barbara is not a poet and Jessica is a nurse. Jessica is a nurse and Barbara is not a poet. If Sarah writes a letter, then Barbara is a poet. If Barbara were a poet, then Sarah is writing a letter. Sarah is not writing a letter.