A man and a woman are walking along a sidewalk and talking in the sun
The man and woman are smiling.
A man and a woman walking along a sidewalk and talking in the sun doesn't imply that the man and woman are smiling, since they could have any variety of facial expressions.
exists e1 e2 x1 x2 x3 x4 x5 x6 x7 x8.(n_sun(x8) & in(e2,x8) & Actor(e2,x5) & v_talk(e2) & subset_of(x7,x5) & n_woman(x7) & subset_of(x6,x5) & n_man(x6) & along(e1,x4) & n_sidewalk(x4) & Actor(e1,x1) & v_walk(e1) & subset_of(x3,x1) & n_woman(x3) & subset_of(x2,x1) & n_man(x2))
exists e1 x1 x2 x3.(n_woman(x3) & n_man(x2) & subset_of(x3,x1) & subset_of(x2,x1) & Actor(e1,x1) & v_smile(e1))