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: Sarah is a politician. For all x_8, if x_8 works, then x_8 is a politician. For all x_8, if x_8 were a politician, then x_8 is working.
There is at least one x for which x is a politician can be inferred via the existential generalization rule. For all x_8, x_8 will work if and only if x_8 is a politician can be inferred via the universal biconditional introduction rule. For all x_8, x_8 is a politician if and only if x_8 will work can be inferred via the universal biconditional introduction rule.