MAYBE

Problem:
 a__zeros() -> cons(0(),zeros())
 a__and(tt(),X) -> mark(X)
 a__length(nil()) -> 0()
 a__length(cons(N,L)) -> s(a__length(mark(L)))
 mark(zeros()) -> a__zeros()
 mark(and(X1,X2)) -> a__and(mark(X1),X2)
 mark(length(X)) -> a__length(mark(X))
 mark(cons(X1,X2)) -> cons(mark(X1),X2)
 mark(0()) -> 0()
 mark(tt()) -> tt()
 mark(nil()) -> nil()
 mark(s(X)) -> s(mark(X))
 a__zeros() -> zeros()
 a__and(X1,X2) -> and(X1,X2)
 a__length(X) -> length(X)

Proof:
 DP Processor:
  DPs:
   a__and#(tt(),X) -> mark#(X)
   a__length#(cons(N,L)) -> mark#(L)
   a__length#(cons(N,L)) -> a__length#(mark(L))
   mark#(zeros()) -> a__zeros#()
   mark#(and(X1,X2)) -> mark#(X1)
   mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
   mark#(length(X)) -> mark#(X)
   mark#(length(X)) -> a__length#(mark(X))
   mark#(cons(X1,X2)) -> mark#(X1)
   mark#(s(X)) -> mark#(X)
  TRS:
   a__zeros() -> cons(0(),zeros())
   a__and(tt(),X) -> mark(X)
   a__length(nil()) -> 0()
   a__length(cons(N,L)) -> s(a__length(mark(L)))
   mark(zeros()) -> a__zeros()
   mark(and(X1,X2)) -> a__and(mark(X1),X2)
   mark(length(X)) -> a__length(mark(X))
   mark(cons(X1,X2)) -> cons(mark(X1),X2)
   mark(0()) -> 0()
   mark(tt()) -> tt()
   mark(nil()) -> nil()
   mark(s(X)) -> s(mark(X))
   a__zeros() -> zeros()
   a__and(X1,X2) -> and(X1,X2)
   a__length(X) -> length(X)
  EDG Processor:
   DPs:
    a__and#(tt(),X) -> mark#(X)
    a__length#(cons(N,L)) -> mark#(L)
    a__length#(cons(N,L)) -> a__length#(mark(L))
    mark#(zeros()) -> a__zeros#()
    mark#(and(X1,X2)) -> mark#(X1)
    mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
    mark#(length(X)) -> mark#(X)
    mark#(length(X)) -> a__length#(mark(X))
    mark#(cons(X1,X2)) -> mark#(X1)
    mark#(s(X)) -> mark#(X)
   TRS:
    a__zeros() -> cons(0(),zeros())
    a__and(tt(),X) -> mark(X)
    a__length(nil()) -> 0()
    a__length(cons(N,L)) -> s(a__length(mark(L)))
    mark(zeros()) -> a__zeros()
    mark(and(X1,X2)) -> a__and(mark(X1),X2)
    mark(length(X)) -> a__length(mark(X))
    mark(cons(X1,X2)) -> cons(mark(X1),X2)
    mark(0()) -> 0()
    mark(tt()) -> tt()
    mark(nil()) -> nil()
    mark(s(X)) -> s(mark(X))
    a__zeros() -> zeros()
    a__and(X1,X2) -> and(X1,X2)
    a__length(X) -> length(X)
   graph:
    a__length#(cons(N,L)) -> a__length#(mark(L)) ->
    a__length#(cons(N,L)) -> mark#(L)
    a__length#(cons(N,L)) -> a__length#(mark(L)) ->
    a__length#(cons(N,L)) -> a__length#(mark(L))
    a__length#(cons(N,L)) -> mark#(L) ->
    mark#(zeros()) -> a__zeros#()
    a__length#(cons(N,L)) -> mark#(L) ->
    mark#(and(X1,X2)) -> mark#(X1)
    a__length#(cons(N,L)) -> mark#(L) ->
    mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
    a__length#(cons(N,L)) -> mark#(L) ->
    mark#(length(X)) -> mark#(X)
    a__length#(cons(N,L)) -> mark#(L) ->
    mark#(length(X)) -> a__length#(mark(X))
    a__length#(cons(N,L)) -> mark#(L) ->
    mark#(cons(X1,X2)) -> mark#(X1)
    a__length#(cons(N,L)) -> mark#(L) ->
    mark#(s(X)) -> mark#(X)
    mark#(length(X)) -> a__length#(mark(X)) ->
    a__length#(cons(N,L)) -> mark#(L)
    mark#(length(X)) -> a__length#(mark(X)) ->
    a__length#(cons(N,L)) -> a__length#(mark(L))
    mark#(length(X)) -> mark#(X) -> mark#(zeros()) -> a__zeros#()
    mark#(length(X)) -> mark#(X) -> mark#(and(X1,X2)) -> mark#(X1)
    mark#(length(X)) -> mark#(X) ->
    mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
    mark#(length(X)) -> mark#(X) -> mark#(length(X)) -> mark#(X)
    mark#(length(X)) -> mark#(X) ->
    mark#(length(X)) -> a__length#(mark(X))
    mark#(length(X)) -> mark#(X) -> mark#(cons(X1,X2)) -> mark#(X1)
    mark#(length(X)) -> mark#(X) -> mark#(s(X)) -> mark#(X)
    mark#(and(X1,X2)) -> mark#(X1) -> mark#(zeros()) -> a__zeros#()
    mark#(and(X1,X2)) -> mark#(X1) -> mark#(and(X1,X2)) -> mark#(X1)
    mark#(and(X1,X2)) -> mark#(X1) ->
    mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
    mark#(and(X1,X2)) -> mark#(X1) -> mark#(length(X)) -> mark#(X)
    mark#(and(X1,X2)) -> mark#(X1) ->
    mark#(length(X)) -> a__length#(mark(X))
    mark#(and(X1,X2)) -> mark#(X1) -> mark#(cons(X1,X2)) -> mark#(X1)
    mark#(and(X1,X2)) -> mark#(X1) ->
    mark#(s(X)) -> mark#(X)
    mark#(and(X1,X2)) -> a__and#(mark(X1),X2) -> a__and#(tt(),X) -> mark#(X)
    mark#(s(X)) -> mark#(X) -> mark#(zeros()) -> a__zeros#()
    mark#(s(X)) -> mark#(X) -> mark#(and(X1,X2)) -> mark#(X1)
    mark#(s(X)) -> mark#(X) -> mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
    mark#(s(X)) -> mark#(X) -> mark#(length(X)) -> mark#(X)
    mark#(s(X)) -> mark#(X) -> mark#(length(X)) -> a__length#(mark(X))
    mark#(s(X)) -> mark#(X) -> mark#(cons(X1,X2)) -> mark#(X1)
    mark#(s(X)) -> mark#(X) -> mark#(s(X)) -> mark#(X)
    mark#(cons(X1,X2)) -> mark#(X1) -> mark#(zeros()) -> a__zeros#()
    mark#(cons(X1,X2)) -> mark#(X1) ->
    mark#(and(X1,X2)) -> mark#(X1)
    mark#(cons(X1,X2)) -> mark#(X1) ->
    mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
    mark#(cons(X1,X2)) -> mark#(X1) -> mark#(length(X)) -> mark#(X)
    mark#(cons(X1,X2)) -> mark#(X1) ->
    mark#(length(X)) -> a__length#(mark(X))
    mark#(cons(X1,X2)) -> mark#(X1) ->
    mark#(cons(X1,X2)) -> mark#(X1)
    mark#(cons(X1,X2)) -> mark#(X1) -> mark#(s(X)) -> mark#(X)
    a__and#(tt(),X) -> mark#(X) -> mark#(zeros()) -> a__zeros#()
    a__and#(tt(),X) -> mark#(X) -> mark#(and(X1,X2)) -> mark#(X1)
    a__and#(tt(),X) -> mark#(X) ->
    mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
    a__and#(tt(),X) -> mark#(X) -> mark#(length(X)) -> mark#(X)
    a__and#(tt(),X) -> mark#(X) ->
    mark#(length(X)) -> a__length#(mark(X))
    a__and#(tt(),X) -> mark#(X) -> mark#(cons(X1,X2)) -> mark#(X1)
    a__and#(tt(),X) -> mark#(X) -> mark#(s(X)) -> mark#(X)
   SCC Processor:
    #sccs: 1
    #rules: 9
    #arcs: 47/100
    DPs:
     a__length#(cons(N,L)) -> a__length#(mark(L))
     a__length#(cons(N,L)) -> mark#(L)
     mark#(s(X)) -> mark#(X)
     mark#(cons(X1,X2)) -> mark#(X1)
     mark#(length(X)) -> a__length#(mark(X))
     mark#(length(X)) -> mark#(X)
     mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
     a__and#(tt(),X) -> mark#(X)
     mark#(and(X1,X2)) -> mark#(X1)
    TRS:
     a__zeros() -> cons(0(),zeros())
     a__and(tt(),X) -> mark(X)
     a__length(nil()) -> 0()
     a__length(cons(N,L)) -> s(a__length(mark(L)))
     mark(zeros()) -> a__zeros()
     mark(and(X1,X2)) -> a__and(mark(X1),X2)
     mark(length(X)) -> a__length(mark(X))
     mark(cons(X1,X2)) -> cons(mark(X1),X2)
     mark(0()) -> 0()
     mark(tt()) -> tt()
     mark(nil()) -> nil()
     mark(s(X)) -> s(mark(X))
     a__zeros() -> zeros()
     a__and(X1,X2) -> and(X1,X2)
     a__length(X) -> length(X)
    Matrix Interpretation Processor:
     dimension: 1
     interpretation:
      [a__length#](x0) = x0 + 1,
      
      [mark#](x0) = x0 + 1,
      
      [a__and#](x0, x1) = x0 + x1,
      
      [length](x0) = x0 + 1,
      
      [and](x0, x1) = x0 + x1,
      
      [s](x0) = x0,
      
      [a__length](x0) = x0 + 1,
      
      [nil] = 0,
      
      [mark](x0) = x0 + 1,
      
      [a__and](x0, x1) = x0 + x1,
      
      [tt] = 1,
      
      [cons](x0, x1) = x0 + x1 + 1,
      
      [zeros] = 0,
      
      [0] = 0,
      
      [a__zeros] = 1
     orientation:
      a__length#(cons(N,L)) = L + N + 2 >= L + 2 = a__length#(mark(L))
      
      a__length#(cons(N,L)) = L + N + 2 >= L + 1 = mark#(L)
      
      mark#(s(X)) = X + 1 >= X + 1 = mark#(X)
      
      mark#(cons(X1,X2)) = X1 + X2 + 2 >= X1 + 1 = mark#(X1)
      
      mark#(length(X)) = X + 2 >= X + 2 = a__length#(mark(X))
      
      mark#(length(X)) = X + 2 >= X + 1 = mark#(X)
      
      mark#(and(X1,X2)) = X1 + X2 + 1 >= X1 + X2 + 1 = a__and#(mark(X1),X2)
      
      a__and#(tt(),X) = X + 1 >= X + 1 = mark#(X)
      
      mark#(and(X1,X2)) = X1 + X2 + 1 >= X1 + 1 = mark#(X1)
      
      a__zeros() = 1 >= 1 = cons(0(),zeros())
      
      a__and(tt(),X) = X + 1 >= X + 1 = mark(X)
      
      a__length(nil()) = 1 >= 0 = 0()
      
      a__length(cons(N,L)) = L + N + 2 >= L + 2 = s(a__length(mark(L)))
      
      mark(zeros()) = 1 >= 1 = a__zeros()
      
      mark(and(X1,X2)) = X1 + X2 + 1 >= X1 + X2 + 1 = a__and(mark(X1),X2)
      
      mark(length(X)) = X + 2 >= X + 2 = a__length(mark(X))
      
      mark(cons(X1,X2)) = X1 + X2 + 2 >= X1 + X2 + 2 = cons(mark(X1),X2)
      
      mark(0()) = 1 >= 0 = 0()
      
      mark(tt()) = 2 >= 1 = tt()
      
      mark(nil()) = 1 >= 0 = nil()
      
      mark(s(X)) = X + 1 >= X + 1 = s(mark(X))
      
      a__zeros() = 1 >= 0 = zeros()
      
      a__and(X1,X2) = X1 + X2 >= X1 + X2 = and(X1,X2)
      
      a__length(X) = X + 1 >= X + 1 = length(X)
     problem:
      DPs:
       a__length#(cons(N,L)) -> a__length#(mark(L))
       mark#(s(X)) -> mark#(X)
       mark#(length(X)) -> a__length#(mark(X))
       mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
       a__and#(tt(),X) -> mark#(X)
       mark#(and(X1,X2)) -> mark#(X1)
      TRS:
       a__zeros() -> cons(0(),zeros())
       a__and(tt(),X) -> mark(X)
       a__length(nil()) -> 0()
       a__length(cons(N,L)) -> s(a__length(mark(L)))
       mark(zeros()) -> a__zeros()
       mark(and(X1,X2)) -> a__and(mark(X1),X2)
       mark(length(X)) -> a__length(mark(X))
       mark(cons(X1,X2)) -> cons(mark(X1),X2)
       mark(0()) -> 0()
       mark(tt()) -> tt()
       mark(nil()) -> nil()
       mark(s(X)) -> s(mark(X))
       a__zeros() -> zeros()
       a__and(X1,X2) -> and(X1,X2)
       a__length(X) -> length(X)
     Matrix Interpretation Processor:
      dimension: 1
      interpretation:
       [a__length#](x0) = 0,
       
       [mark#](x0) = 1,
       
       [a__and#](x0, x1) = 1,
       
       [length](x0) = 0,
       
       [and](x0, x1) = 0,
       
       [s](x0) = 0,
       
       [a__length](x0) = 0,
       
       [nil] = 1,
       
       [mark](x0) = 1,
       
       [a__and](x0, x1) = 1,
       
       [tt] = 0,
       
       [cons](x0, x1) = 0,
       
       [zeros] = 0,
       
       [0] = 0,
       
       [a__zeros] = 1
      orientation:
       a__length#(cons(N,L)) = 0 >= 0 = a__length#(mark(L))
       
       mark#(s(X)) = 1 >= 1 = mark#(X)
       
       mark#(length(X)) = 1 >= 0 = a__length#(mark(X))
       
       mark#(and(X1,X2)) = 1 >= 1 = a__and#(mark(X1),X2)
       
       a__and#(tt(),X) = 1 >= 1 = mark#(X)
       
       mark#(and(X1,X2)) = 1 >= 1 = mark#(X1)
       
       a__zeros() = 1 >= 0 = cons(0(),zeros())
       
       a__and(tt(),X) = 1 >= 1 = mark(X)
       
       a__length(nil()) = 0 >= 0 = 0()
       
       a__length(cons(N,L)) = 0 >= 0 = s(a__length(mark(L)))
       
       mark(zeros()) = 1 >= 1 = a__zeros()
       
       mark(and(X1,X2)) = 1 >= 1 = a__and(mark(X1),X2)
       
       mark(length(X)) = 1 >= 0 = a__length(mark(X))
       
       mark(cons(X1,X2)) = 1 >= 0 = cons(mark(X1),X2)
       
       mark(0()) = 1 >= 0 = 0()
       
       mark(tt()) = 1 >= 0 = tt()
       
       mark(nil()) = 1 >= 1 = nil()
       
       mark(s(X)) = 1 >= 0 = s(mark(X))
       
       a__zeros() = 1 >= 0 = zeros()
       
       a__and(X1,X2) = 1 >= 0 = and(X1,X2)
       
       a__length(X) = 0 >= 0 = length(X)
      problem:
       DPs:
        a__length#(cons(N,L)) -> a__length#(mark(L))
        mark#(s(X)) -> mark#(X)
        mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
        a__and#(tt(),X) -> mark#(X)
        mark#(and(X1,X2)) -> mark#(X1)
       TRS:
        a__zeros() -> cons(0(),zeros())
        a__and(tt(),X) -> mark(X)
        a__length(nil()) -> 0()
        a__length(cons(N,L)) -> s(a__length(mark(L)))
        mark(zeros()) -> a__zeros()
        mark(and(X1,X2)) -> a__and(mark(X1),X2)
        mark(length(X)) -> a__length(mark(X))
        mark(cons(X1,X2)) -> cons(mark(X1),X2)
        mark(0()) -> 0()
        mark(tt()) -> tt()
        mark(nil()) -> nil()
        mark(s(X)) -> s(mark(X))
        a__zeros() -> zeros()
        a__and(X1,X2) -> and(X1,X2)
        a__length(X) -> length(X)
      Matrix Interpretation Processor:
       dimension: 1
       interpretation:
        [a__length#](x0) = 0,
        
        [mark#](x0) = x0,
        
        [a__and#](x0, x1) = x0 + x1,
        
        [length](x0) = 0,
        
        [and](x0, x1) = x0 + x1,
        
        [s](x0) = x0,
        
        [a__length](x0) = 0,
        
        [nil] = 0,
        
        [mark](x0) = x0,
        
        [a__and](x0, x1) = x0 + x1,
        
        [tt] = 1,
        
        [cons](x0, x1) = 0,
        
        [zeros] = 0,
        
        [0] = 0,
        
        [a__zeros] = 0
       orientation:
        a__length#(cons(N,L)) = 0 >= 0 = a__length#(mark(L))
        
        mark#(s(X)) = X >= X = mark#(X)
        
        mark#(and(X1,X2)) = X1 + X2 >= X1 + X2 = a__and#(mark(X1),X2)
        
        a__and#(tt(),X) = X + 1 >= X = mark#(X)
        
        mark#(and(X1,X2)) = X1 + X2 >= X1 = mark#(X1)
        
        a__zeros() = 0 >= 0 = cons(0(),zeros())
        
        a__and(tt(),X) = X + 1 >= X = mark(X)
        
        a__length(nil()) = 0 >= 0 = 0()
        
        a__length(cons(N,L)) = 0 >= 0 = s(a__length(mark(L)))
        
        mark(zeros()) = 0 >= 0 = a__zeros()
        
        mark(and(X1,X2)) = X1 + X2 >= X1 + X2 = a__and(mark(X1),X2)
        
        mark(length(X)) = 0 >= 0 = a__length(mark(X))
        
        mark(cons(X1,X2)) = 0 >= 0 = cons(mark(X1),X2)
        
        mark(0()) = 0 >= 0 = 0()
        
        mark(tt()) = 1 >= 1 = tt()
        
        mark(nil()) = 0 >= 0 = nil()
        
        mark(s(X)) = X >= X = s(mark(X))
        
        a__zeros() = 0 >= 0 = zeros()
        
        a__and(X1,X2) = X1 + X2 >= X1 + X2 = and(X1,X2)
        
        a__length(X) = 0 >= 0 = length(X)
       problem:
        DPs:
         a__length#(cons(N,L)) -> a__length#(mark(L))
         mark#(s(X)) -> mark#(X)
         mark#(and(X1,X2)) -> a__and#(mark(X1),X2)
         mark#(and(X1,X2)) -> mark#(X1)
        TRS:
         a__zeros() -> cons(0(),zeros())
         a__and(tt(),X) -> mark(X)
         a__length(nil()) -> 0()
         a__length(cons(N,L)) -> s(a__length(mark(L)))
         mark(zeros()) -> a__zeros()
         mark(and(X1,X2)) -> a__and(mark(X1),X2)
         mark(length(X)) -> a__length(mark(X))
         mark(cons(X1,X2)) -> cons(mark(X1),X2)
         mark(0()) -> 0()
         mark(tt()) -> tt()
         mark(nil()) -> nil()
         mark(s(X)) -> s(mark(X))
         a__zeros() -> zeros()
         a__and(X1,X2) -> and(X1,X2)
         a__length(X) -> length(X)
       Matrix Interpretation Processor:
        dimension: 1
        interpretation:
         [a__length#](x0) = 1,
         
         [mark#](x0) = 1,
         
         [a__and#](x0, x1) = 0,
         
         [length](x0) = 0,
         
         [and](x0, x1) = 0,
         
         [s](x0) = 0,
         
         [a__length](x0) = x0,
         
         [nil] = 1,
         
         [mark](x0) = 1,
         
         [a__and](x0, x1) = 1,
         
         [tt] = 1,
         
         [cons](x0, x1) = x0,
         
         [zeros] = 0,
         
         [0] = 1,
         
         [a__zeros] = 1
        orientation:
         a__length#(cons(N,L)) = 1 >= 1 = a__length#(mark(L))
         
         mark#(s(X)) = 1 >= 1 = mark#(X)
         
         mark#(and(X1,X2)) = 1 >= 0 = a__and#(mark(X1),X2)
         
         mark#(and(X1,X2)) = 1 >= 1 = mark#(X1)
         
         a__zeros() = 1 >= 1 = cons(0(),zeros())
         
         a__and(tt(),X) = 1 >= 1 = mark(X)
         
         a__length(nil()) = 1 >= 1 = 0()
         
         a__length(cons(N,L)) = N >= 0 = s(a__length(mark(L)))
         
         mark(zeros()) = 1 >= 1 = a__zeros()
         
         mark(and(X1,X2)) = 1 >= 1 = a__and(mark(X1),X2)
         
         mark(length(X)) = 1 >= 1 = a__length(mark(X))
         
         mark(cons(X1,X2)) = 1 >= 1 = cons(mark(X1),X2)
         
         mark(0()) = 1 >= 1 = 0()
         
         mark(tt()) = 1 >= 1 = tt()
         
         mark(nil()) = 1 >= 1 = nil()
         
         mark(s(X)) = 1 >= 0 = s(mark(X))
         
         a__zeros() = 1 >= 0 = zeros()
         
         a__and(X1,X2) = 1 >= 0 = and(X1,X2)
         
         a__length(X) = X >= 0 = length(X)
        problem:
         DPs:
          a__length#(cons(N,L)) -> a__length#(mark(L))
          mark#(s(X)) -> mark#(X)
          mark#(and(X1,X2)) -> mark#(X1)
         TRS:
          a__zeros() -> cons(0(),zeros())
          a__and(tt(),X) -> mark(X)
          a__length(nil()) -> 0()
          a__length(cons(N,L)) -> s(a__length(mark(L)))
          mark(zeros()) -> a__zeros()
          mark(and(X1,X2)) -> a__and(mark(X1),X2)
          mark(length(X)) -> a__length(mark(X))
          mark(cons(X1,X2)) -> cons(mark(X1),X2)
          mark(0()) -> 0()
          mark(tt()) -> tt()
          mark(nil()) -> nil()
          mark(s(X)) -> s(mark(X))
          a__zeros() -> zeros()
          a__and(X1,X2) -> and(X1,X2)
          a__length(X) -> length(X)
        Matrix Interpretation Processor:
         dimension: 1
         interpretation:
          [a__length#](x0) = 0,
          
          [mark#](x0) = x0 + 1,
          
          [length](x0) = 0,
          
          [and](x0, x1) = x0 + x1 + 1,
          
          [s](x0) = x0,
          
          [a__length](x0) = 1,
          
          [nil] = 1,
          
          [mark](x0) = x0 + 1,
          
          [a__and](x0, x1) = x0 + x1 + 1,
          
          [tt] = 0,
          
          [cons](x0, x1) = x0,
          
          [zeros] = 0,
          
          [0] = 1,
          
          [a__zeros] = 1
         orientation:
          a__length#(cons(N,L)) = 0 >= 0 = a__length#(mark(L))
          
          mark#(s(X)) = X + 1 >= X + 1 = mark#(X)
          
          mark#(and(X1,X2)) = X1 + X2 + 2 >= X1 + 1 = mark#(X1)
          
          a__zeros() = 1 >= 1 = cons(0(),zeros())
          
          a__and(tt(),X) = X + 1 >= X + 1 = mark(X)
          
          a__length(nil()) = 1 >= 1 = 0()
          
          a__length(cons(N,L)) = 1 >= 1 = s(a__length(mark(L)))
          
          mark(zeros()) = 1 >= 1 = a__zeros()
          
          mark(and(X1,X2)) = X1 + X2 + 2 >= X1 + X2 + 2 = a__and(mark(X1),X2)
          
          mark(length(X)) = 1 >= 1 = a__length(mark(X))
          
          mark(cons(X1,X2)) = X1 + 1 >= X1 + 1 = cons(mark(X1),X2)
          
          mark(0()) = 2 >= 1 = 0()
          
          mark(tt()) = 1 >= 0 = tt()
          
          mark(nil()) = 2 >= 1 = nil()
          
          mark(s(X)) = X + 1 >= X + 1 = s(mark(X))
          
          a__zeros() = 1 >= 0 = zeros()
          
          a__and(X1,X2) = X1 + X2 + 1 >= X1 + X2 + 1 = and(X1,X2)
          
          a__length(X) = 1 >= 0 = length(X)
         problem:
          DPs:
           a__length#(cons(N,L)) -> a__length#(mark(L))
           mark#(s(X)) -> mark#(X)
          TRS:
           a__zeros() -> cons(0(),zeros())
           a__and(tt(),X) -> mark(X)
           a__length(nil()) -> 0()
           a__length(cons(N,L)) -> s(a__length(mark(L)))
           mark(zeros()) -> a__zeros()
           mark(and(X1,X2)) -> a__and(mark(X1),X2)
           mark(length(X)) -> a__length(mark(X))
           mark(cons(X1,X2)) -> cons(mark(X1),X2)
           mark(0()) -> 0()
           mark(tt()) -> tt()
           mark(nil()) -> nil()
           mark(s(X)) -> s(mark(X))
           a__zeros() -> zeros()
           a__and(X1,X2) -> and(X1,X2)
           a__length(X) -> length(X)
         Open