(VAR YS X XS Y L X1 X2) (RULES active(app(nil,YS)) -> mark(YS) active(app(cons(X,XS),YS)) -> mark(cons(X,app(XS,YS))) active(from(X)) -> mark(cons(X,from(s(X)))) active(zWadr(nil,YS)) -> mark(nil) active(zWadr(XS,nil)) -> mark(nil) active(zWadr(cons(X,XS),cons(Y,YS))) -> mark(cons(app(Y,cons(X,nil)),zWadr(XS,YS))) active(prefix(L)) -> mark(cons(nil,zWadr(L,prefix(L)))) active(app(X1,X2)) -> app(active(X1),X2) active(app(X1,X2)) -> app(X1,active(X2)) active(cons(X1,X2)) -> cons(active(X1),X2) active(from(X)) -> from(active(X)) active(s(X)) -> s(active(X)) active(zWadr(X1,X2)) -> zWadr(active(X1),X2) active(zWadr(X1,X2)) -> zWadr(X1,active(X2)) active(prefix(X)) -> prefix(active(X)) app(mark(X1),X2) -> mark(app(X1,X2)) app(X1,mark(X2)) -> mark(app(X1,X2)) cons(mark(X1),X2) -> mark(cons(X1,X2)) from(mark(X)) -> mark(from(X)) s(mark(X)) -> mark(s(X)) zWadr(mark(X1),X2) -> mark(zWadr(X1,X2)) zWadr(X1,mark(X2)) -> mark(zWadr(X1,X2)) prefix(mark(X)) -> mark(prefix(X)) proper(app(X1,X2)) -> app(proper(X1),proper(X2)) proper(nil) -> ok(nil) proper(cons(X1,X2)) -> cons(proper(X1),proper(X2)) proper(from(X)) -> from(proper(X)) proper(s(X)) -> s(proper(X)) proper(zWadr(X1,X2)) -> zWadr(proper(X1),proper(X2)) proper(prefix(X)) -> prefix(proper(X)) app(ok(X1),ok(X2)) -> ok(app(X1,X2)) cons(ok(X1),ok(X2)) -> ok(cons(X1,X2)) from(ok(X)) -> ok(from(X)) s(ok(X)) -> ok(s(X)) zWadr(ok(X1),ok(X2)) -> ok(zWadr(X1,X2)) prefix(ok(X)) -> ok(prefix(X)) top(mark(X)) -> top(proper(X)) top(ok(X)) -> top(active(X)) )