premise: A group of mountain climbers rests at the summit. hypothesis: A scuba diver runs out of air.
contradiction: The subject is either mountain climbers or a scuba diver.|contradiction: A single scuba diver cannot be a group of mountain climbers. He cannot be at the summit of a mountain. He won't be resting while he runs out of air.|contradiction: People can not be mountain climbers and scuba diver at the same time.