(VAR X Y Z X1 X2) (RULES active(dbl(0)) -> mark(0) active(dbl(s(X))) -> mark(s(s(dbl(X)))) active(dbls(nil)) -> mark(nil) active(dbls(cons(X,Y))) -> mark(cons(dbl(X),dbls(Y))) active(sel(0,cons(X,Y))) -> mark(X) active(sel(s(X),cons(Y,Z))) -> mark(sel(X,Z)) active(indx(nil,X)) -> mark(nil) active(indx(cons(X,Y),Z)) -> mark(cons(sel(X,Z),indx(Y,Z))) active(from(X)) -> mark(cons(X,from(s(X)))) active(dbl1(0)) -> mark(01) active(dbl1(s(X))) -> mark(s1(s1(dbl1(X)))) active(sel1(0,cons(X,Y))) -> mark(X) active(sel1(s(X),cons(Y,Z))) -> mark(sel1(X,Z)) active(quote(0)) -> mark(01) active(quote(s(X))) -> mark(s1(quote(X))) active(quote(dbl(X))) -> mark(dbl1(X)) active(quote(sel(X,Y))) -> mark(sel1(X,Y)) active(dbl(X)) -> dbl(active(X)) active(dbls(X)) -> dbls(active(X)) active(sel(X1,X2)) -> sel(active(X1),X2) active(sel(X1,X2)) -> sel(X1,active(X2)) active(indx(X1,X2)) -> indx(active(X1),X2) active(dbl1(X)) -> dbl1(active(X)) active(s1(X)) -> s1(active(X)) active(sel1(X1,X2)) -> sel1(active(X1),X2) active(sel1(X1,X2)) -> sel1(X1,active(X2)) active(quote(X)) -> quote(active(X)) dbl(mark(X)) -> mark(dbl(X)) dbls(mark(X)) -> mark(dbls(X)) sel(mark(X1),X2) -> mark(sel(X1,X2)) sel(X1,mark(X2)) -> mark(sel(X1,X2)) indx(mark(X1),X2) -> mark(indx(X1,X2)) dbl1(mark(X)) -> mark(dbl1(X)) s1(mark(X)) -> mark(s1(X)) sel1(mark(X1),X2) -> mark(sel1(X1,X2)) sel1(X1,mark(X2)) -> mark(sel1(X1,X2)) quote(mark(X)) -> mark(quote(X)) proper(dbl(X)) -> dbl(proper(X)) proper(0) -> ok(0) proper(s(X)) -> s(proper(X)) proper(dbls(X)) -> dbls(proper(X)) proper(nil) -> ok(nil) proper(cons(X1,X2)) -> cons(proper(X1),proper(X2)) proper(sel(X1,X2)) -> sel(proper(X1),proper(X2)) proper(indx(X1,X2)) -> indx(proper(X1),proper(X2)) proper(from(X)) -> from(proper(X)) proper(dbl1(X)) -> dbl1(proper(X)) proper(01) -> ok(01) proper(s1(X)) -> s1(proper(X)) proper(sel1(X1,X2)) -> sel1(proper(X1),proper(X2)) proper(quote(X)) -> quote(proper(X)) dbl(ok(X)) -> ok(dbl(X)) s(ok(X)) -> ok(s(X)) dbls(ok(X)) -> ok(dbls(X)) cons(ok(X1),ok(X2)) -> ok(cons(X1,X2)) sel(ok(X1),ok(X2)) -> ok(sel(X1,X2)) indx(ok(X1),ok(X2)) -> ok(indx(X1,X2)) from(ok(X)) -> ok(from(X)) dbl1(ok(X)) -> ok(dbl1(X)) s1(ok(X)) -> ok(s1(X)) sel1(ok(X1),ok(X2)) -> ok(sel1(X1,X2)) quote(ok(X)) -> ok(quote(X)) top(mark(X)) -> top(proper(X)) top(ok(X)) -> top(active(X)) )