context: A skater performs a stunt off a cement wall covered in graffiti.
hypothesis: It is impossible that a skateboarder falling off his board, onto the concrete below.
valid_hypothesis: It is impossible that a skateboarder falling off his board, onto the concrete below.
invalid_hypothesis: We believe that a skateboarder falling off his board, onto the concrete below.
hypothesis_assertion: A skateboarder falling off his board, onto the concrete below.