premise: A man is performing an aerial skateboard trick on a ramp with several other people behind him.
hypothesis: A man with a blue cap on is performing a skateboard trick in front of a crowd of people.
explanation_1: A skateboarder is not assumed to be wearing a blue cap.  Several people does not necessarily imply a crowd.
explanation_2: The first sentence does not say that the man is wearing a blue cap or if the number of people qualifies as a crowd.
explanation_3: Just because a man is performing an aerial skateboard trick does not mean he is has a blue cap on.
premise_logic: exists e1 s1 s2 x1 x2 x3 x4 x5 x6.(n_male(x6) & n_people(x6) & with(e1,x5) & behind(x5,x6) & -(x5 = x6) & n_people(x5) & a_several(s2) & Theme(s2,x5) & on(e1,x4) & n_ramp(x4) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_trick(x2) & of(x2,x3) & n_skateboard(x3) & a_aerial(s1) & Theme(s1,x2) & n_man(x1))
hypothesis_logic: exists e1 s1 s2 x1 x2 x3 x4 x5 x6 x7 x8.(in(e1,x6) & of(x6,x7) & of(x7,x8) & n_people(x8) & n_crowd(x7) & n_front(x6) & Theme(e1,x4) & Actor(e1,x1) & v_perform(e1) & n_trick(x4) & of(x4,x5) & n_skateboard(x5) & with(x1,x2) & Theme(s2,x3) & a_on(s2) & (x2 = x3) & n_cap(x2) & a_blue(s1) & Theme(s1,x2) & n_man(x1))