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_16, x_16 will read a book or x_16 is a carpenter. For all x_16, x_16 is a mechanic if and only if x_16 will read a book. There is at least one x_16 for which x_16 is not a taxi driver. For all x_16, x_16 is a mechanic if and only if x_16 is a taxi driver.
For all x_16, if x_16 were a mechanic, then x_16 is reading a book can be inferred via the universal biconditional elimination rule. For all x_16, if x_16 were a mechanic, then x_16 is a taxi driver can be inferred via the universal biconditional elimination rule. For all x_16, if x_16 reads a book, then x_16 is a mechanic can be inferred via the universal biconditional elimination rule. For all x_16, if x_16 were a taxi driver, then x_16 is a mechanic can be inferred via the universal biconditional elimination rule. There is at least one x_16 for which x_16 is not a mechanic can be inferred via the existential biconditional elimination rule.