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: There is at least one x for which if x sleeps, then x is a poet. For all x, x is a poet or x will not sleep. For all x, if x were a poet, then x is sleeping.
For all x, if x sleeps, then x is a poet can be inferred via the universal rewriting rule. There is at least one x for which x will sleep if and only if x is a poet can be inferred via the existential biconditional introduction rule. There is at least one x for which x is a poet if and only if x will sleep can be inferred via the existential biconditional introduction rule.