A black woman with a scarf on her head stands on a sidewalk, smiling.
White woman with a bare head sitting on a sidewalk, frowning.
A black woman is not a white woman.  Having a scarf on her head means she does not have a bare head.  She cannot be smiling and frowning at the same time.
exists e1 e2 s1 x1 x2 x3 x4.(for(e1,e2) & Actor(e2,x1) & v_smile(e2) & on(e1,x4) & n_sidewalk(x4) & Actor(e1,x1) & v_stand(e1) & with(x1,x2) & on(x2,x3) & n_head(x3) & of(x3,x1) & n_female(x1) & n_scarf(x2) & n_woman(x1) & a_black(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & on(e1,x5) & rel(x5,x6) & n_frowning(x6) & n_sidewalk(x5) & Actor(e1,x4) & v_sit(e1) & (x1 = x4) & with(x1,x3) & n_head(x3) & a_bare(s1) & Theme(s1,x3) & n_woman(x1) & (x1 = x2) & ne_per_white(x2))