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_6, x_6 is a scientist if and only if x_6 will make tea. There is at least one x_6 for which x_6 is not a scientist. For all x_6, x_6 will sleep if and only if x_6 will make tea.
For all x_6, if x_6 were a scientist, then x_6 is making tea can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 sleeps, then x_6 is making tea can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 makes tea, then x_6 is a scientist can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 makes tea, then x_6 is sleeping can be inferred via the universal biconditional elimination rule. There is at least one x_6 for which x_6 will not make tea can be inferred via the existential biconditional elimination rule.