Many people are gathered in a crowded building.
People are gathered together in significant numbers.
gathered together in significant numbers  is a rephrasing of Many people are gathered .
exists e1 s1 x1 x2.(in(e1,x2) & n_building(x2) & a_crowded(s1) & Theme(s1,x2) & Theme(e1,x1) & v_gather(e1) & n_people(x1) & n_quantity(x1))
exists e1 s1 s2 x1 x2.(in(e1,x2) & n_number(x2) & a_significant(s2) & Theme(s2,x2) & a_together(s1) & Manner(e1,s1) & Theme(e1,x1) & v_gather(e1) & n_people(x1))