premise: A crowd of interested people surrounds a man swinging a sledgehammer.
hypothesis: A man swinging a sledgehammer.
explanation_1: A crowd is surrounding a man swinging a sledgehammer.
explanation_2: A man is swinging a sledgehammer in both sentences.  Sentence two leaves out the details, but is not a complete sentence.
explanation_3: The man is swinging a sledgehammer, regardless of whether or not people are watching him.
premise_logic: exists e1 e2 s1 x1 x2 x3 x4 x5.(Theme(e2,x3) & Actor(e2,x1) & v_surround(e2) & Theme(e1,x5) & Actor(e1,x4) & v_swing(e1) & n_sledgehammer(x5) & (x3 = x4) & n_man(x3) & of(x1,x2) & n_people(x2) & a_interested(s1) & Theme(s1,x2) & n_crowd(x1))
hypothesis_logic: exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_swing(e1) & n_sledgehammer(x3) & (x1 = x2) & n_man(x1))