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_18, x_18 will not work. Michael is a police officer if and only if David is fast. For all x_18, x_18 is a sailor if and only if x_18 will work. For all x_18, x_18 is a sailor if and only if x_18 is fast. Michael is a police officer or John is running.
If Michael were a police officer, then David is fast can be inferred via the biconditional elimination rule. If David were fast, then Michael is a police officer can be inferred via the biconditional elimination rule. For all x_18, if x_18 were a sailor, then x_18 is working can be inferred via the universal biconditional elimination rule. For all x_18, if x_18 were a sailor, then x_18 is fast can be inferred via the universal biconditional elimination rule. For all x_18, if x_18 works, then x_18 is a sailor can be inferred via the universal biconditional elimination rule. For all x_18, if x_18 were fast, then x_18 is a sailor can be inferred via the universal biconditional elimination rule. For all x_18, x_18 is not a sailor can be inferred via the universal biconditional elimination rule.