premise: a lone motorcyclist jumping through the air in front of a large crowd.
hypothesis: The man is wearing a helmet.
explanation_1: A person can ride a motorcycle without a helmet.
explanation_2: A lone motorcyclist jumping through the air in front of a large crowd does not imply that the man is wearing a helmet.
explanation_3: A lone motorcyclist does not have to be a man.   Just because the motorcyclist is jumping through the air it does not mean they are wearing a helmet.
premise_logic: exists e1 s1 s2 x1 x2 x3 x4 x5.(n_air(x3) & a_topic(x1) & in(e1,x4) & of(x4,x5) & n_crowd(x5) & a_large(s2) & Theme(s2,x5) & n_front(x4) & through(e1,x3) & Actor(e1,x2) & v_jump(e1) & (x1 = x2) & n_motorcyclist(x1) & a_lone(s1) & Theme(s1,x1))
hypothesis_logic: exists e1 x1 x2.(n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_helmet(x2))