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 y, if y were a carpenter, then y is making tea. There is at least one y for which if y makes tea, then y is a carpenter. For all y, y is a carpenter or y is not curious.
For all y, if y were curious, then y is a carpenter can be inferred via the universal rewriting rule. There is at least one y for which y will make tea 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 will make tea can be inferred via the existential biconditional introduction rule.