(VAR X XS N X1 X2) (RULES active(from(X)) -> mark(cons(X,from(s(X)))) active(head(cons(X,XS))) -> mark(X) active(2nd(cons(X,XS))) -> mark(head(XS)) active(take(0,XS)) -> mark(nil) active(take(s(N),cons(X,XS))) -> mark(cons(X,take(N,XS))) active(sel(0,cons(X,XS))) -> mark(X) active(sel(s(N),cons(X,XS))) -> mark(sel(N,XS)) mark(from(X)) -> active(from(mark(X))) mark(cons(X1,X2)) -> active(cons(mark(X1),X2)) mark(s(X)) -> active(s(mark(X))) mark(head(X)) -> active(head(mark(X))) mark(2nd(X)) -> active(2nd(mark(X))) mark(take(X1,X2)) -> active(take(mark(X1),mark(X2))) mark(0) -> active(0) mark(nil) -> active(nil) mark(sel(X1,X2)) -> active(sel(mark(X1),mark(X2))) from(mark(X)) -> from(X) from(active(X)) -> from(X) cons(mark(X1),X2) -> cons(X1,X2) cons(X1,mark(X2)) -> cons(X1,X2) cons(active(X1),X2) -> cons(X1,X2) cons(X1,active(X2)) -> cons(X1,X2) s(mark(X)) -> s(X) s(active(X)) -> s(X) head(mark(X)) -> head(X) head(active(X)) -> head(X) 2nd(mark(X)) -> 2nd(X) 2nd(active(X)) -> 2nd(X) take(mark(X1),X2) -> take(X1,X2) take(X1,mark(X2)) -> take(X1,X2) take(active(X1),X2) -> take(X1,X2) take(X1,active(X2)) -> take(X1,X2) sel(mark(X1),X2) -> sel(X1,X2) sel(X1,mark(X2)) -> sel(X1,X2) sel(active(X1),X2) -> sel(X1,X2) sel(X1,active(X2)) -> sel(X1,X2) )