Well, if a pair has two atomic sentences, any of the three possibilities can happen: the pair is either an entailment, or a contradiction or a neutral pair.
If the pair has two non-atomic sentences, we're in trouble, can't say much.
If the pair has one atomic and one non-atomic sentence, then either the non-atomic entails the atomic or they are neutral. This is because the atomic cannot (usually?) entail the non-atomic one. and our definition of contradicitons says we cannot have a contradiction between an atomic and a non-atomic sentence.
Well, if a pair has two atomic sentences, any of the three possibilities can happen: the pair is either an entailment, or a contradiction or a neutral pair.
If the pair has two non-atomic sentences, we're in trouble, can't say much.
If the pair has one atomic and one non-atomic sentence, then either the non-atomic entails the atomic or they are neutral. This is because the atomic cannot (usually?) entail the non-atomic one. and our definition of contradicitons says we cannot have a contradiction between an atomic and a non-atomic sentence.