That does n't look like mud on the horse rider.
The rider of the horse has some substance on them.
mud implies some substance on them.
exists x1 x3 x4.(n_rider(x3) & of(x3,x4) & n_horse(x4) & n_thing(x1) & -exists e1 x2.(like(e1,x2) & on(x2,x3) & n_mud(x2) & Actor(e1,x1) & v_look(e1)))
exists e1 x1 x2 x3.(n_thing(x1) & n_horse(x2) & n_rider(x1) & Theme(e1,x3) & Actor(e1,x1) & v_have(e1) & on(x3,x1) & n_substance(x3) & of(x1,x2))