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: Susan is reading a book if and only if Susan is fast. For all x_10, if x_10 reads a book, then x_10 is fast.
If Susan reads a book, then Susan is fast can be inferred via the biconditional elimination rule. If Susan were fast, then Susan is reading a book can be inferred via the biconditional elimination rule.