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 it is cold, then Patricia is sleeping. Patricia is not sleeping. If Patricia sleeps, then it is cold. If James reads a book, then it is cold.
It is not cold can be inferred via the modus tollens rule. It is cold if and only if Patricia is sleeping can be inferred via the biconditional introduction rule. Patricia is sleeping if and only if it is cold can be inferred via the biconditional introduction rule.