TIMEOUT

We are left with following problem, upon which TcT provides the
certificate TIMEOUT.

Strict Trs:
  { append(@l1, @l2) -> append#1(@l1, @l2)
  , append#1(::(@x, @xs), @l2) -> ::(@x, append(@xs, @l2))
  , append#1(nil(), @l2) -> @l2
  , append3(@l1, @l2) -> append3#1(@l1, @l2)
  , append3#1(::(@x, @xs), @l2) -> ::(@x, append3(@xs, @l2))
  , append3#1(nil(), @l2) -> @l2
  , append4(@l1, @l2) -> append4#1(@l1, @l2)
  , append4#1(::(@x, @xs), @l2) -> ::(@x, append4(@xs, @l2))
  , append4#1(nil(), @l2) -> @l2
  , attach(@n, @l) -> attach#1(@l, @n)
  , attach#1(::(@x, @xs), @n) -> ::(tuple#2(@n, @x), attach(@n, @xs))
  , attach#1(nil(), @n) -> nil()
  , attach3(@n, @l) -> attach3#1(@l, @n)
  , attach3#1(::(@x, @xs), @n) ->
    ::(tuple#2(@n, @x), attach3(@n, @xs))
  , attach3#1(nil(), @n) -> nil()
  , attach4(@n, @l) -> attach4#1(@l, @n)
  , attach4#1(::(@x, @xs), @n) ->
    ::(tuple#2(@n, @x), attach4(@n, @xs))
  , attach4#1(nil(), @n) -> nil()
  , pairs(@l) -> pairs#1(@l)
  , pairs#1(::(@x, @xs)) -> append(attach(@x, @xs), pairs(@xs))
  , pairs#1(nil()) -> nil()
  , pairs'(@l) -> pairs'#1(@l)
  , pairs'#1(::(@x, @xs)) -> append(pairs'(@xs), attach(@x, @xs))
  , pairs'#1(nil()) -> nil()
  , pairs_aux(@l, @acc) -> pairs_aux#1(@l, @acc)
  , pairs_aux#1(::(@x, @xs), @acc) ->
    pairs_aux(@xs, append(attach(@x, @xs), @acc))
  , pairs_aux#1(nil(), @acc) -> @acc
  , quadruples(@l) -> quadruples#1(@l)
  , quadruples#1(::(@x, @xs)) ->
    append4(attach4(@x, triples(@xs)), quadruples(@xs))
  , quadruples#1(nil()) -> nil()
  , triples(@l) -> triples#1(@l)
  , triples#1(::(@x, @xs)) ->
    append3(attach3(@x, pairs(@xs)), triples(@xs))
  , triples#1(nil()) -> nil() }
Obligation:
  innermost runtime complexity
Answer:
  TIMEOUT

Computation stopped due to timeout after 300.0 seconds.

Arrrr..