premise: A person is surfing on a large wave.
hypothesis: The person is in a surfing competition.
explanation_1: You can not infer it's a competition.
explanation_2: Just because a person is surfing on a large wave doesn't mean the person is in a surfing competition.
explanation_3: A person surfing does not have to be in a competition.
premise_logic: exists e1 s1 x1 x2.(on(e1,x2) & n_wave(x2) & a_large(s1) & Theme(s1,x2) & Actor(e1,x1) & v_surf(e1) & n_person(x1))
hypothesis_logic: exists p1 x1.(n_person(x1) & exists s1 x2.(in(x1,x2) & n_competition(x2) & a_surfing(s1) & Theme(s1,x2)))