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: Thomas is reading a book if and only if Susan is a cashier. Thomas is reading a book if and only if Patricia is running. For all x_7, x_7 will go running if and only if x_7 will play a game. Susan is not a cashier.
If Thomas reads a book, then Susan is a cashier can be inferred via the biconditional elimination rule. If Thomas reads a book, then Patricia is running can be inferred via the biconditional elimination rule. If Susan were a cashier, then Thomas is reading a book can be inferred via the biconditional elimination rule. If Patricia goes running, then Thomas is reading a book can be inferred via the biconditional elimination rule. Thomas is not reading a book can be inferred via the biconditional elimination rule. For all x_7, if x_7 goes running, then x_7 is playing a game can be inferred via the universal biconditional elimination rule. For all x_7, if x_7 plays a game, then x_7 is running can be inferred via the universal biconditional elimination rule.