MAYBE

Problem:
 app(nil(),xs) -> nil()
 app(cons(x,xs),ys) -> cons(x,app(xs,ys))
 rev(nil()) -> nil()
 rev(cons(x,xs)) -> append(xs,rev(cons(x,nil())))
 shuffle(nil()) -> nil()
 shuffle(cons(x,xs)) -> cons(x,shuffle(rev(xs)))

Proof:
 DP Processor:
  DPs:
   app#(cons(x,xs),ys) -> app#(xs,ys)
   rev#(cons(x,xs)) -> rev#(cons(x,nil()))
   shuffle#(cons(x,xs)) -> rev#(xs)
   shuffle#(cons(x,xs)) -> shuffle#(rev(xs))
  TRS:
   app(nil(),xs) -> nil()
   app(cons(x,xs),ys) -> cons(x,app(xs,ys))
   rev(nil()) -> nil()
   rev(cons(x,xs)) -> append(xs,rev(cons(x,nil())))
   shuffle(nil()) -> nil()
   shuffle(cons(x,xs)) -> cons(x,shuffle(rev(xs)))
  TDG Processor:
   DPs:
    app#(cons(x,xs),ys) -> app#(xs,ys)
    rev#(cons(x,xs)) -> rev#(cons(x,nil()))
    shuffle#(cons(x,xs)) -> rev#(xs)
    shuffle#(cons(x,xs)) -> shuffle#(rev(xs))
   TRS:
    app(nil(),xs) -> nil()
    app(cons(x,xs),ys) -> cons(x,app(xs,ys))
    rev(nil()) -> nil()
    rev(cons(x,xs)) -> append(xs,rev(cons(x,nil())))
    shuffle(nil()) -> nil()
    shuffle(cons(x,xs)) -> cons(x,shuffle(rev(xs)))
   graph:
    shuffle#(cons(x,xs)) -> shuffle#(rev(xs)) ->
    shuffle#(cons(x,xs)) -> shuffle#(rev(xs))
    shuffle#(cons(x,xs)) -> shuffle#(rev(xs)) ->
    shuffle#(cons(x,xs)) -> rev#(xs)
    shuffle#(cons(x,xs)) -> rev#(xs) ->
    rev#(cons(x,xs)) -> rev#(cons(x,nil()))
    rev#(cons(x,xs)) -> rev#(cons(x,nil())) ->
    rev#(cons(x,xs)) -> rev#(cons(x,nil()))
    app#(cons(x,xs),ys) -> app#(xs,ys) -> app#(cons(x,xs),ys) -> app#(xs,ys)
   CDG Processor:
    DPs:
     app#(cons(x,xs),ys) -> app#(xs,ys)
     rev#(cons(x,xs)) -> rev#(cons(x,nil()))
     shuffle#(cons(x,xs)) -> rev#(xs)
     shuffle#(cons(x,xs)) -> shuffle#(rev(xs))
    TRS:
     app(nil(),xs) -> nil()
     app(cons(x,xs),ys) -> cons(x,app(xs,ys))
     rev(nil()) -> nil()
     rev(cons(x,xs)) -> append(xs,rev(cons(x,nil())))
     shuffle(nil()) -> nil()
     shuffle(cons(x,xs)) -> cons(x,shuffle(rev(xs)))
    graph:
     shuffle#(cons(x,xs)) -> rev#(xs) ->
     rev#(cons(x,xs)) -> rev#(cons(x,nil()))
     rev#(cons(x,xs)) -> rev#(cons(x,nil())) -> rev#(cons(x,xs)) -> rev#(cons(x,nil()))
    SCC Processor:
     #sccs: 1
     #rules: 1
     #arcs: 2/16
     DPs:
      rev#(cons(x,xs)) -> rev#(cons(x,nil()))
     TRS:
      app(nil(),xs) -> nil()
      app(cons(x,xs),ys) -> cons(x,app(xs,ys))
      rev(nil()) -> nil()
      rev(cons(x,xs)) -> append(xs,rev(cons(x,nil())))
      shuffle(nil()) -> nil()
      shuffle(cons(x,xs)) -> cons(x,shuffle(rev(xs)))
     Open