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, if x were a scientist, then x is a bartender. If Karen were not a scientist, then Thomas is a poet. Karen is not a bartender. For all x, if x were a bartender, then x is a scientist.
For all x, x is a scientist if and only if x is a bartender can be inferred via the universal biconditional introduction rule. For all x, x is a bartender if and only if x is a scientist can be inferred via the universal biconditional introduction rule.