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 if y were a poet, then y is a carpenter. For all y, if y were a carpenter, then y is a poet. For all y, if y were a carpenter, then y is a poet.
There is at least one y for which y is a poet if and only if y is a carpenter can be inferred via the existential biconditional introduction rule. There is at least one y for which y is a poet if and only if y is a carpenter can be inferred via the existential biconditional introduction rule. There is at least one y for which y is a carpenter if and only if y is a poet can be inferred via the existential biconditional introduction rule. There is at least one y for which y is a carpenter if and only if y is a poet can be inferred via the existential biconditional introduction rule.