A man wearing no shirt rides a skateboard with a brown dog.
The man's dog is a lab.
Just because a man wearing no shirt rides a skateboard with a brown dog does not imply that the man's dog is a lab.
exists e1 s1 x1 x2 x3 x4.(Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & with(x3,x4) & n_dog(x4) & a_brown(s1) & Theme(s1,x4) & n_skateboard(x3) & -exists e2 x5.(Theme(e2,x5) & Actor(e2,x2) & v_wear(e2) & n_shirt(x5)) & (x1 = x2) & n_man(x1))
exists p1 x1 x2.(n_dog(x2) & of(x2,x1) & n_man(x1) & exists x3.((x2 = x3) & n_lab(x3)))