Example (cont.d)
(_x) (trailer-truck(x) __
(_s) (set(s) __count(s, 18) _
(_y) (y __s __ (wheel(y) _ part(y, x))))).
" for all x, if x is a trailer truck, then there exists a set of 18 elements, and for all y, if y is a member of s, then y is a wheel and y is a part of x "