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 an electrician if and only if y will make tea. For all y, y is an electrician or y is not a carpenter.
For all y, if y were a carpenter, then y is an electrician can be inferred via the universal rewriting rule. There is at least one y for which if y were an electrician, 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 an electrician can be inferred via the existential biconditional elimination rule.