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: Karen is running if and only if David is a writer. David is not a writer. Jessica is playing squash if and only if Jennifer is a doctor. Jennifer is a doctor if and only if Karen is running.
If Karen goes running, then David is a writer can be inferred via the biconditional elimination rule. If Jessica plays squash, then Jennifer is a doctor can be inferred via the biconditional elimination rule. If Jennifer were a doctor, then Karen is running can be inferred via the biconditional elimination rule. If David were a writer, then Karen is running can be inferred via the biconditional elimination rule. If Jennifer were a doctor, then Jessica is playing squash can be inferred via the biconditional elimination rule. If Karen goes running, then Jennifer is a doctor can be inferred via the biconditional elimination rule. Karen is not running can be inferred via the biconditional elimination rule.