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, x is rich or x will play tennis. For all x, x will read a book if and only if x will play tennis. There is at least one x for which x will not read a book. For all x, x is not rich or x will climb a mountain.
For all x, x will play tennis or x will climb a mountain can be inferred via the universal resolution rule. For all x, if x reads a book, then x is playing tennis can be inferred via the universal biconditional elimination rule. For all x, if x plays tennis, then x is reading a book can be inferred via the universal biconditional elimination rule. There is at least one x for which x will not play tennis can be inferred via the existential biconditional elimination rule.