A man walking by a stop sign.
A man standing by a blue sign
One cannot be standing by a sign while also walking by a sign.
exists x1 x2 x3 x4.(a_topic(x1) & by(x1,x3) & n_sign(x3) & of(x3,x4) & n_stop(x4) & n_walking(x1) & of(x1,x2) & n_man(x2))
exists s1 x1 x2 x3.(a_topic(x1) & by(x1,x3) & n_sign(x3) & a_blue(s1) & Theme(s1,x3) & n_standing(x1) & of(x1,x2) & n_man(x2))