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: David is happy or David is driving a car. If Jessica sleeps, then it is late. If David drives a car, then Jessica is sleeping. If David were happy, then Jessica is sleeping.
If David drives a car, then it is late can be inferred via the transitivity rule. If David were happy, then it is late can be inferred via the transitivity rule. Jessica is sleeping can be inferred via the disjunction elimination rule.