context: A uniformed competitor in motocross has crossed a jump in the course and is astride his motorcycle in midair, with several young men looking on.
hypothesis: It is impossible that a man is riding a bicycle in the park.
valid_hypothesis: It is impossible that a man is riding a bicycle in the park.
invalid_hypothesis: It is likely that a man is riding a bicycle in the park.
hypothesis_assertion: A man is riding a bicycle in the park.