A man signed the yellow guitar that day.
One evening a man signs portraits.
if you are signing a yellow guitar you are not signing portraits
exists e1 s1 x1 x2 x3.(n_day(x3) & n_guitar(x2) & a_yellow(s1) & Theme(s1,x2) & Time(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_sign(e1) & n_man(x1))
all x1 x2.((n_sign(x1) & of(x1,x2) & n_man(x2)) -> exists x3 x4.(a_topic(x3) & Time(x3,x4) & n_portrait(x4) & for(x3,x1) & n_evening(x3) & card_eq_1(x3)))