premise: A man on a skateboard performs a trick in the air against the backdrop of a bright blue sky.
hypothesis: A man is a good skateboarder
explanation_1: You can not infer he is good.
explanation_2: Not all skateboarders are good.
explanation_3: Not all men performing tricks are good skateboarders; this man may be a poor skateboarder.
premise_logic: exists e1 s1 s2 x1 x2 x3 x4 x5 x6.(n_backdrop(x5) & n_air(x4) & against(e1,x5) & of(x5,x6) & n_sky(x6) & a_blue(s2) & Theme(s2,x6) & a_bright(s1) & Theme(s1,x6) & in(e1,x4) & Theme(e1,x3) & Actor(e1,x1) & v_perform(e1) & n_trick(x3) & on(x1,x2) & n_skateboard(x2) & n_man(x1))
hypothesis_logic: exists p1 x1.(exists s1 x2.((x1 = x2) & n_skateboarder(x2) & a_good(s1) & Theme(s1,x2)) & n_man(x1))