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 y for which y is a janitor if and only if y will make tea. For all y, if y were a janitor, then y is making tea.
There is at least one y for which if y were a janitor, then y is making tea can be inferred via the existential biconditional elimination rule. There is at least one y for which if y makes tea, then y is a janitor can be inferred via the existential biconditional elimination rule.