Problem:
 active(zeros()) -> mark(cons(0(),zeros()))
 active(tail(cons(X,XS))) -> mark(XS)
 mark(zeros()) -> active(zeros())
 mark(cons(X1,X2)) -> active(cons(mark(X1),X2))
 mark(0()) -> active(0())
 mark(tail(X)) -> active(tail(mark(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)
 tail(mark(X)) -> tail(X)
 tail(active(X)) -> tail(X)

Proof:
 Bounds Processor:
  bound: 4
  enrichment: match
  automaton:
   final states: {6,5,4,3}
   transitions:
    mark3(14) -> 23*
    active1(10) -> 4*
    active1(11) -> 4*
    cons4(28,13) -> 24*
    cons4(14,13) -> 24*
    01() -> 11*
    03() -> 28*
    zeros1() -> 10*
    mark1(12) -> 3*
    cons1(11,10) -> 12*
    active2(22) -> 3*
    active2(14) -> 21*
    cons2(21,10) -> 22*
    cons2(14,13) -> 15*
    active0(2) -> 3*
    active0(1) -> 3*
    mark2(15) -> 4*
    mark2(11) -> 21*
    zeros0() -> 1*
    02() -> 14*
    mark0(2) -> 4*
    mark0(1) -> 4*
    zeros2() -> 13*
    cons0(1,2) -> 5*
    cons0(2,1) -> 5*
    cons0(1,1) -> 5*
    cons0(2,2) -> 5*
    cons3(23,13) -> 24*
    cons3(14,10) -> 22*
    cons3(11,10) -> 22*
    00() -> 2*
    active3(24) -> 4*
    active3(28) -> 23*
    tail0(2) -> 6*
    tail0(1) -> 6*
  problem:
   
  Qed