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 x, x will climb a mountain if and only if x is a lawyer. For all x, x is not a cashier. There is at least one x for which x is a cashier or x will not climb a mountain.
There is at least one x for which if x climbs a mountain, then x is a cashier can be inferred via the existential rewriting rule. For all x, if x climbs a mountain, then x is a lawyer can be inferred via the universal biconditional elimination rule. For all x, if x were a lawyer, then x is climbing a mountain can be inferred via the universal biconditional elimination rule.