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, if x were a writer, then x is making tea. There is at least one x for which if x were poor, then x is making tea. For all x, if x makes tea, then x is poor.
For all x, if x were a writer, then x is poor can be inferred via the universal transitivity rule. There is at least one x for which x is poor if and only if x will make tea can be inferred via the existential biconditional introduction rule. There is at least one x for which x will make tea if and only if x is poor can be inferred via the existential biconditional introduction rule.