Men playing volleyball in the sand.
Men are playing volleyball.
There is nothing in sentence 2 that cannot be inferred from sentence 1; in both cases, men are playing volleyball.
exists e1 x1 x2 x3 x4.(n_sand(x4) & a_topic(x1) & in(e1,x4) & Theme(e1,x3) & Actor(e1,x2) & v_play(e1) & n_volleyball(x3) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_volleyball(x2) & n_man(x1))