premise: The dog's mouth is open like he is yawning. hypothesis: a dog is yawning because he is tired from a walk.
neutral: A dog yawning does not imply he is tired from a walk.|neutral: The dog's mouth could be open in the motion of barking, not only yawning.  There is no statement indicating that the dog is returning from a walk only that it looks like he is yawning, but this does not imply he is tired only that his mouth resembles a yawn.|neutral: Dog is not necessarily yawning because he is tired from a walk.