(VAR X Y L X1 X2) (RULES active(eq(0,0)) -> mark(true) active(eq(s(X),s(Y))) -> mark(eq(X,Y)) active(eq(X,Y)) -> mark(false) active(inf(X)) -> mark(cons(X,inf(s(X)))) active(take(0,X)) -> mark(nil) active(take(s(X),cons(Y,L))) -> mark(cons(Y,take(X,L))) active(length(nil)) -> mark(0) active(length(cons(X,L))) -> mark(s(length(L))) mark(eq(X1,X2)) -> active(eq(X1,X2)) mark(0) -> active(0) mark(true) -> active(true) mark(s(X)) -> active(s(X)) mark(false) -> active(false) mark(inf(X)) -> active(inf(mark(X))) mark(cons(X1,X2)) -> active(cons(X1,X2)) mark(take(X1,X2)) -> active(take(mark(X1),mark(X2))) mark(nil) -> active(nil) mark(length(X)) -> active(length(mark(X))) eq(mark(X1),X2) -> eq(X1,X2) eq(X1,mark(X2)) -> eq(X1,X2) eq(active(X1),X2) -> eq(X1,X2) eq(X1,active(X2)) -> eq(X1,X2) s(mark(X)) -> s(X) s(active(X)) -> s(X) inf(mark(X)) -> inf(X) inf(active(X)) -> inf(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) 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) length(mark(X)) -> length(X) length(active(X)) -> length(X) )