(VAR X N XS Y)
(RULES 
from(X) -> cons(X)
sel(0,cons(X)) -> X
sel(s(N),cons(X)) -> sel(N,XS)
minus(X,0) -> 0
minus(s(X),s(Y)) -> minus(X,Y)
quot(0,s(Y)) -> 0
quot(s(X),s(Y)) -> s(quot(minus(X,Y),s(Y)))
zWquot(XS,nil) -> nil
zWquot(nil,XS) -> nil
zWquot(cons(X),cons(Y)) -> cons(quot(X,Y))
)