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_8, x_8 is a scientist if and only if x_8 is poor. For all x_8, x_8 is a scientist. For all x_8, x_8 is rich.
For all x_8, x_8 is a scientist and x_8 is rich can be inferred via the universal conjunction rule. For all x_8, x_8 is rich and x_8 is a scientist can be inferred via the universal conjunction rule. For all x_8, if x_8 were a scientist, then x_8 is poor can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were poor, then x_8 is a scientist can be inferred via the universal biconditional elimination rule.