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_12, x_12 is happy if and only if x_12 is an artist. For all x_12, if x_12 were happy, then x_12 is sleeping. For all x_12, x_12 is fast or x_12 is an artist. For all x_12, x_12 is fast if and only if x_12 will sleep.
For all x_12, if x_12 were happy, then x_12 is an artist can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 were fast, then x_12 is sleeping can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 were an artist, then x_12 is happy can be inferred via the universal biconditional elimination rule. For all x_12, if x_12 sleeps, then x_12 is fast can be inferred via the universal biconditional elimination rule.