premise: A man wearing a blue jacket fishing in a river having a conversation with his friend with no shirt. hypothesis: A man is having a conversation with his friend while fishing.
entailment: Fishing in a river is a type of fishing.|entailment: A man is having a conversation while fishing in both sentences.  The first is a fragment, the second is correct.|entailment: This man is having a conversation with his friend while he is fishing; what they are wearing is less relevant to the topic.