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: If Linda plays squash, then John is working. If John works, then Linda is playing squash. Joseph is playing a game if and only if Linda is playing squash. If William reads a book, then John is working.
If William reads a book, then Linda is playing squash can be inferred via the transitivity rule. Linda is playing squash if and only if John is working can be inferred via the biconditional introduction rule. John is working if and only if Linda is playing squash can be inferred via the biconditional introduction rule. If Joseph plays a game, then Linda is playing squash can be inferred via the biconditional elimination rule. If Linda plays squash, then Joseph is playing a game can be inferred via the biconditional elimination rule.