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: It is not late. If it is overcast, then Robert is playing tennis. If Charles were curious, then it is overcast. It is late or Charles is curious.
If Charles were curious, then Robert is playing tennis can be inferred via the transitivity rule. Charles is curious can be inferred via the disjunctive syllogism rule.