We are left with following problem, upon which TcT provides the
certificate YES(O(1),O(n^2)).

Strict Trs:
  { a__first(X1, X2) -> first(X1, X2)
  , a__first(0(), X) -> nil()
  , a__first(s(X), cons(Y, Z)) -> cons(mark(Y), first(X, Z))
  , mark(0()) -> 0()
  , mark(nil()) -> nil()
  , mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2)
  , mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , mark(from(X)) -> a__from(mark(X))
  , a__from(X) -> cons(mark(X), from(s(X)))
  , a__from(X) -> from(X) }
Obligation:
  innermost runtime complexity
Answer:
  YES(O(1),O(n^2))

The weightgap principle applies (using the following nonconstant
growth matrix-interpretation)

The following argument positions are usable:
  Uargs(a__first) = {1, 2}, Uargs(s) = {1}, Uargs(cons) = {1},
  Uargs(a__from) = {1}

TcT has computed the following matrix interpretation satisfying
not(EDA) and not(IDA(1)).

  [a__first](x1, x2) = [1] x1 + [1] x2 + [1]
                                            
                 [0] = [0]                  
                                            
               [nil] = [0]                  
                                            
             [s](x1) = [1] x1 + [0]         
                                            
      [cons](x1, x2) = [1] x1 + [0]         
                                            
          [mark](x1) = [0]                  
                                            
     [first](x1, x2) = [1] x1 + [0]         
                                            
       [a__from](x1) = [1] x1 + [0]         
                                            
          [from](x1) = [1] x1 + [0]         

The order satisfies the following ordering constraints:

            [a__first(X1, X2)] =  [1] X1 + [1] X2 + [1]         
                               >  [1] X1 + [0]                  
                               =  [first(X1, X2)]               
                                                                
            [a__first(0(), X)] =  [1] X + [1]                   
                               >  [0]                           
                               =  [nil()]                       
                                                                
  [a__first(s(X), cons(Y, Z))] =  [1] X + [1] Y + [1]           
                               >  [0]                           
                               =  [cons(mark(Y), first(X, Z))]  
                                                                
                   [mark(0())] =  [0]                           
                               >= [0]                           
                               =  [0()]                         
                                                                
                 [mark(nil())] =  [0]                           
                               >= [0]                           
                               =  [nil()]                       
                                                                
                  [mark(s(X))] =  [0]                           
                               >= [0]                           
                               =  [s(mark(X))]                  
                                                                
          [mark(cons(X1, X2))] =  [0]                           
                               >= [0]                           
                               =  [cons(mark(X1), X2)]          
                                                                
         [mark(first(X1, X2))] =  [0]                           
                               ?  [1]                           
                               =  [a__first(mark(X1), mark(X2))]
                                                                
               [mark(from(X))] =  [0]                           
                               >= [0]                           
                               =  [a__from(mark(X))]            
                                                                
                  [a__from(X)] =  [1] X + [0]                   
                               >= [0]                           
                               =  [cons(mark(X), from(s(X)))]   
                                                                
                  [a__from(X)] =  [1] X + [0]                   
                               >= [1] X + [0]                   
                               =  [from(X)]                     
                                                                

Further, it can be verified that all rules not oriented are covered by the weightgap condition.

We are left with following problem, upon which TcT provides the
certificate YES(O(1),O(n^2)).

Strict Trs:
  { mark(0()) -> 0()
  , mark(nil()) -> nil()
  , mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2)
  , mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , mark(from(X)) -> a__from(mark(X))
  , a__from(X) -> cons(mark(X), from(s(X)))
  , a__from(X) -> from(X) }
Weak Trs:
  { a__first(X1, X2) -> first(X1, X2)
  , a__first(0(), X) -> nil()
  , a__first(s(X), cons(Y, Z)) -> cons(mark(Y), first(X, Z)) }
Obligation:
  innermost runtime complexity
Answer:
  YES(O(1),O(n^2))

The weightgap principle applies (using the following nonconstant
growth matrix-interpretation)

The following argument positions are usable:
  Uargs(a__first) = {1, 2}, Uargs(s) = {1}, Uargs(cons) = {1},
  Uargs(a__from) = {1}

TcT has computed the following matrix interpretation satisfying
not(EDA) and not(IDA(1)).

  [a__first](x1, x2) = [1] x1 + [1] x2 + [4]
                                            
                 [0] = [0]                  
                                            
               [nil] = [0]                  
                                            
             [s](x1) = [1] x1 + [0]         
                                            
      [cons](x1, x2) = [1] x1 + [0]         
                                            
          [mark](x1) = [1] x1 + [0]         
                                            
     [first](x1, x2) = [1] x1 + [1] x2 + [0]
                                            
       [a__from](x1) = [1] x1 + [0]         
                                            
          [from](x1) = [1] x1 + [4]         

The order satisfies the following ordering constraints:

            [a__first(X1, X2)] =  [1] X1 + [1] X2 + [4]         
                               >  [1] X1 + [1] X2 + [0]         
                               =  [first(X1, X2)]               
                                                                
            [a__first(0(), X)] =  [1] X + [4]                   
                               >  [0]                           
                               =  [nil()]                       
                                                                
  [a__first(s(X), cons(Y, Z))] =  [1] X + [1] Y + [4]           
                               >  [1] Y + [0]                   
                               =  [cons(mark(Y), first(X, Z))]  
                                                                
                   [mark(0())] =  [0]                           
                               >= [0]                           
                               =  [0()]                         
                                                                
                 [mark(nil())] =  [0]                           
                               >= [0]                           
                               =  [nil()]                       
                                                                
                  [mark(s(X))] =  [1] X + [0]                   
                               >= [1] X + [0]                   
                               =  [s(mark(X))]                  
                                                                
          [mark(cons(X1, X2))] =  [1] X1 + [0]                  
                               >= [1] X1 + [0]                  
                               =  [cons(mark(X1), X2)]          
                                                                
         [mark(first(X1, X2))] =  [1] X1 + [1] X2 + [0]         
                               ?  [1] X1 + [1] X2 + [4]         
                               =  [a__first(mark(X1), mark(X2))]
                                                                
               [mark(from(X))] =  [1] X + [4]                   
                               >  [1] X + [0]                   
                               =  [a__from(mark(X))]            
                                                                
                  [a__from(X)] =  [1] X + [0]                   
                               >= [1] X + [0]                   
                               =  [cons(mark(X), from(s(X)))]   
                                                                
                  [a__from(X)] =  [1] X + [0]                   
                               ?  [1] X + [4]                   
                               =  [from(X)]                     
                                                                

Further, it can be verified that all rules not oriented are covered by the weightgap condition.

We are left with following problem, upon which TcT provides the
certificate YES(O(1),O(n^2)).

Strict Trs:
  { mark(0()) -> 0()
  , mark(nil()) -> nil()
  , mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2)
  , mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , a__from(X) -> cons(mark(X), from(s(X)))
  , a__from(X) -> from(X) }
Weak Trs:
  { a__first(X1, X2) -> first(X1, X2)
  , a__first(0(), X) -> nil()
  , a__first(s(X), cons(Y, Z)) -> cons(mark(Y), first(X, Z))
  , mark(from(X)) -> a__from(mark(X)) }
Obligation:
  innermost runtime complexity
Answer:
  YES(O(1),O(n^2))

The weightgap principle applies (using the following nonconstant
growth matrix-interpretation)

The following argument positions are usable:
  Uargs(a__first) = {1, 2}, Uargs(s) = {1}, Uargs(cons) = {1},
  Uargs(a__from) = {1}

TcT has computed the following matrix interpretation satisfying
not(EDA) and not(IDA(1)).

  [a__first](x1, x2) = [1] x1 + [1] x2 + [4]
                                            
                 [0] = [0]                  
                                            
               [nil] = [0]                  
                                            
             [s](x1) = [1] x1 + [0]         
                                            
      [cons](x1, x2) = [1] x1 + [0]         
                                            
          [mark](x1) = [1] x1 + [0]         
                                            
     [first](x1, x2) = [1] x1 + [1] x2 + [0]
                                            
       [a__from](x1) = [1] x1 + [1]         
                                            
          [from](x1) = [1] x1 + [1]         

The order satisfies the following ordering constraints:

            [a__first(X1, X2)] =  [1] X1 + [1] X2 + [4]         
                               >  [1] X1 + [1] X2 + [0]         
                               =  [first(X1, X2)]               
                                                                
            [a__first(0(), X)] =  [1] X + [4]                   
                               >  [0]                           
                               =  [nil()]                       
                                                                
  [a__first(s(X), cons(Y, Z))] =  [1] X + [1] Y + [4]           
                               >  [1] Y + [0]                   
                               =  [cons(mark(Y), first(X, Z))]  
                                                                
                   [mark(0())] =  [0]                           
                               >= [0]                           
                               =  [0()]                         
                                                                
                 [mark(nil())] =  [0]                           
                               >= [0]                           
                               =  [nil()]                       
                                                                
                  [mark(s(X))] =  [1] X + [0]                   
                               >= [1] X + [0]                   
                               =  [s(mark(X))]                  
                                                                
          [mark(cons(X1, X2))] =  [1] X1 + [0]                  
                               >= [1] X1 + [0]                  
                               =  [cons(mark(X1), X2)]          
                                                                
         [mark(first(X1, X2))] =  [1] X1 + [1] X2 + [0]         
                               ?  [1] X1 + [1] X2 + [4]         
                               =  [a__first(mark(X1), mark(X2))]
                                                                
               [mark(from(X))] =  [1] X + [1]                   
                               >= [1] X + [1]                   
                               =  [a__from(mark(X))]            
                                                                
                  [a__from(X)] =  [1] X + [1]                   
                               >  [1] X + [0]                   
                               =  [cons(mark(X), from(s(X)))]   
                                                                
                  [a__from(X)] =  [1] X + [1]                   
                               >= [1] X + [1]                   
                               =  [from(X)]                     
                                                                

Further, it can be verified that all rules not oriented are covered by the weightgap condition.

We are left with following problem, upon which TcT provides the
certificate YES(O(1),O(n^2)).

Strict Trs:
  { mark(0()) -> 0()
  , mark(nil()) -> nil()
  , mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2)
  , mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , a__from(X) -> from(X) }
Weak Trs:
  { a__first(X1, X2) -> first(X1, X2)
  , a__first(0(), X) -> nil()
  , a__first(s(X), cons(Y, Z)) -> cons(mark(Y), first(X, Z))
  , mark(from(X)) -> a__from(mark(X))
  , a__from(X) -> cons(mark(X), from(s(X))) }
Obligation:
  innermost runtime complexity
Answer:
  YES(O(1),O(n^2))

The weightgap principle applies (using the following nonconstant
growth matrix-interpretation)

The following argument positions are usable:
  Uargs(a__first) = {1, 2}, Uargs(s) = {1}, Uargs(cons) = {1},
  Uargs(a__from) = {1}

TcT has computed the following matrix interpretation satisfying
not(EDA) and not(IDA(1)).

  [a__first](x1, x2) = [1] x1 + [1] x2 + [6]
                                            
                 [0] = [0]                  
                                            
               [nil] = [0]                  
                                            
             [s](x1) = [1] x1 + [0]         
                                            
      [cons](x1, x2) = [1] x1 + [0]         
                                            
          [mark](x1) = [1] x1 + [1]         
                                            
     [first](x1, x2) = [1] x1 + [1] x2 + [0]
                                            
       [a__from](x1) = [1] x1 + [3]         
                                            
          [from](x1) = [1] x1 + [3]         

The order satisfies the following ordering constraints:

            [a__first(X1, X2)] =  [1] X1 + [1] X2 + [6]         
                               >  [1] X1 + [1] X2 + [0]         
                               =  [first(X1, X2)]               
                                                                
            [a__first(0(), X)] =  [1] X + [6]                   
                               >  [0]                           
                               =  [nil()]                       
                                                                
  [a__first(s(X), cons(Y, Z))] =  [1] X + [1] Y + [6]           
                               >  [1] Y + [1]                   
                               =  [cons(mark(Y), first(X, Z))]  
                                                                
                   [mark(0())] =  [1]                           
                               >  [0]                           
                               =  [0()]                         
                                                                
                 [mark(nil())] =  [1]                           
                               >  [0]                           
                               =  [nil()]                       
                                                                
                  [mark(s(X))] =  [1] X + [1]                   
                               >= [1] X + [1]                   
                               =  [s(mark(X))]                  
                                                                
          [mark(cons(X1, X2))] =  [1] X1 + [1]                  
                               >= [1] X1 + [1]                  
                               =  [cons(mark(X1), X2)]          
                                                                
         [mark(first(X1, X2))] =  [1] X1 + [1] X2 + [1]         
                               ?  [1] X1 + [1] X2 + [8]         
                               =  [a__first(mark(X1), mark(X2))]
                                                                
               [mark(from(X))] =  [1] X + [4]                   
                               >= [1] X + [4]                   
                               =  [a__from(mark(X))]            
                                                                
                  [a__from(X)] =  [1] X + [3]                   
                               >  [1] X + [1]                   
                               =  [cons(mark(X), from(s(X)))]   
                                                                
                  [a__from(X)] =  [1] X + [3]                   
                               >= [1] X + [3]                   
                               =  [from(X)]                     
                                                                

Further, it can be verified that all rules not oriented are covered by the weightgap condition.

We are left with following problem, upon which TcT provides the
certificate YES(O(1),O(n^2)).

Strict Trs:
  { mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2)
  , mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , a__from(X) -> from(X) }
Weak Trs:
  { a__first(X1, X2) -> first(X1, X2)
  , a__first(0(), X) -> nil()
  , a__first(s(X), cons(Y, Z)) -> cons(mark(Y), first(X, Z))
  , mark(0()) -> 0()
  , mark(nil()) -> nil()
  , mark(from(X)) -> a__from(mark(X))
  , a__from(X) -> cons(mark(X), from(s(X))) }
Obligation:
  innermost runtime complexity
Answer:
  YES(O(1),O(n^2))

We use the processor 'matrix interpretation of dimension 2' to
orient following rules strictly.

Trs:
  { mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , a__from(X) -> from(X) }

The induced complexity on above rules (modulo remaining rules) is
YES(?,O(n^2)) . These rules are moved into the corresponding weak
component(s).

Sub-proof:
----------
  The following argument positions are usable:
    Uargs(a__first) = {1, 2}, Uargs(s) = {1}, Uargs(cons) = {1},
    Uargs(a__from) = {1}
  
  TcT has computed the following constructor-based matrix
  interpretation satisfying not(EDA).
  
    [a__first](x1, x2) = [1 0] x1 + [1 1] x2 + [4]
                         [0 1]      [0 1]      [3]
                                                  
                   [0] = [0]                      
                         [0]                      
                                                  
                 [nil] = [0]                      
                         [0]                      
                                                  
               [s](x1) = [1 4] x1 + [4]           
                         [0 1]      [0]           
                                                  
        [cons](x1, x2) = [1 3] x1 + [0]           
                         [0 1]      [0]           
                                                  
            [mark](x1) = [1 1] x1 + [2]           
                         [0 1]      [0]           
                                                  
       [first](x1, x2) = [1 0] x1 + [1 1] x2 + [4]
                         [0 1]      [0 1]      [3]
                                                  
         [a__from](x1) = [1 6] x1 + [7]           
                         [0 1]      [2]           
                                                  
            [from](x1) = [1 6] x1 + [6]           
                         [0 1]      [2]           
  
  The order satisfies the following ordering constraints:
  
              [a__first(X1, X2)] =  [1 0] X1 + [1 1] X2 + [4]     
                                    [0 1]      [0 1]      [3]     
                                 >= [1 0] X1 + [1 1] X2 + [4]     
                                    [0 1]      [0 1]      [3]     
                                 =  [first(X1, X2)]               
                                                                  
              [a__first(0(), X)] =  [1 1] X + [4]                 
                                    [0 1]     [3]                 
                                 >  [0]                           
                                    [0]                           
                                 =  [nil()]                       
                                                                  
    [a__first(s(X), cons(Y, Z))] =  [1 4] X + [1 4] Y + [8]       
                                    [0 1]     [0 1]     [3]       
                                 >  [1 4] Y + [2]                 
                                    [0 1]     [0]                 
                                 =  [cons(mark(Y), first(X, Z))]  
                                                                  
                     [mark(0())] =  [2]                           
                                    [0]                           
                                 >  [0]                           
                                    [0]                           
                                 =  [0()]                         
                                                                  
                   [mark(nil())] =  [2]                           
                                    [0]                           
                                 >  [0]                           
                                    [0]                           
                                 =  [nil()]                       
                                                                  
                    [mark(s(X))] =  [1 5] X + [6]                 
                                    [0 1]     [0]                 
                                 >= [1 5] X + [6]                 
                                    [0 1]     [0]                 
                                 =  [s(mark(X))]                  
                                                                  
            [mark(cons(X1, X2))] =  [1 4] X1 + [2]                
                                    [0 1]      [0]                
                                 >= [1 4] X1 + [2]                
                                    [0 1]      [0]                
                                 =  [cons(mark(X1), X2)]          
                                                                  
           [mark(first(X1, X2))] =  [1 1] X1 + [1 2] X2 + [9]     
                                    [0 1]      [0 1]      [3]     
                                 >  [1 1] X1 + [1 2] X2 + [8]     
                                    [0 1]      [0 1]      [3]     
                                 =  [a__first(mark(X1), mark(X2))]
                                                                  
                 [mark(from(X))] =  [1 7] X + [10]                
                                    [0 1]     [2]                 
                                 >  [1 7] X + [9]                 
                                    [0 1]     [2]                 
                                 =  [a__from(mark(X))]            
                                                                  
                    [a__from(X)] =  [1 6] X + [7]                 
                                    [0 1]     [2]                 
                                 >  [1 4] X + [2]                 
                                    [0 1]     [0]                 
                                 =  [cons(mark(X), from(s(X)))]   
                                                                  
                    [a__from(X)] =  [1 6] X + [7]                 
                                    [0 1]     [2]                 
                                 >  [1 6] X + [6]                 
                                    [0 1]     [2]                 
                                 =  [from(X)]                     
                                                                  

We return to the main proof.

We are left with following problem, upon which TcT provides the
certificate YES(O(1),O(n^2)).

Strict Trs:
  { mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2) }
Weak Trs:
  { a__first(X1, X2) -> first(X1, X2)
  , a__first(0(), X) -> nil()
  , a__first(s(X), cons(Y, Z)) -> cons(mark(Y), first(X, Z))
  , mark(0()) -> 0()
  , mark(nil()) -> nil()
  , mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , mark(from(X)) -> a__from(mark(X))
  , a__from(X) -> cons(mark(X), from(s(X)))
  , a__from(X) -> from(X) }
Obligation:
  innermost runtime complexity
Answer:
  YES(O(1),O(n^2))

We use the processor 'matrix interpretation of dimension 2' to
orient following rules strictly.

Trs:
  { mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2) }

The induced complexity on above rules (modulo remaining rules) is
YES(?,O(n^2)) . These rules are moved into the corresponding weak
component(s).

Sub-proof:
----------
  The following argument positions are usable:
    Uargs(a__first) = {1, 2}, Uargs(s) = {1}, Uargs(cons) = {1},
    Uargs(a__from) = {1}
  
  TcT has computed the following constructor-based matrix
  interpretation satisfying not(EDA).
  
    [a__first](x1, x2) = [1 0] x1 + [1 7] x2 + [0]
                         [0 1]      [0 1]      [1]
                                                  
                   [0] = [0]                      
                         [0]                      
                                                  
                 [nil] = [0]                      
                         [0]                      
                                                  
               [s](x1) = [1 7] x1 + [7]           
                         [0 1]      [2]           
                                                  
        [cons](x1, x2) = [1 0] x1 + [0 2] x2 + [0]
                         [0 1]      [0 0]      [1]
                                                  
            [mark](x1) = [1 1] x1 + [0]           
                         [0 1]      [0]           
                                                  
       [first](x1, x2) = [1 0] x1 + [1 7] x2 + [0]
                         [0 1]      [0 1]      [1]
                                                  
         [a__from](x1) = [1 3] x1 + [7]           
                         [0 1]      [1]           
                                                  
            [from](x1) = [1 3] x1 + [7]           
                         [0 1]      [1]           
  
  The order satisfies the following ordering constraints:
  
              [a__first(X1, X2)] =  [1 0] X1 + [1 7] X2 + [0]         
                                    [0 1]      [0 1]      [1]         
                                 >= [1 0] X1 + [1 7] X2 + [0]         
                                    [0 1]      [0 1]      [1]         
                                 =  [first(X1, X2)]                   
                                                                      
              [a__first(0(), X)] =  [1 7] X + [0]                     
                                    [0 1]     [1]                     
                                 >= [0]                               
                                    [0]                               
                                 =  [nil()]                           
                                                                      
    [a__first(s(X), cons(Y, Z))] =  [1 7] X + [1 7] Y + [0 2] Z + [14]
                                    [0 1]     [0 1]     [0 0]     [4] 
                                 >  [0 2] X + [1 1] Y + [0 2] Z + [2] 
                                    [0 0]     [0 1]     [0 0]     [1] 
                                 =  [cons(mark(Y), first(X, Z))]      
                                                                      
                     [mark(0())] =  [0]                               
                                    [0]                               
                                 >= [0]                               
                                    [0]                               
                                 =  [0()]                             
                                                                      
                   [mark(nil())] =  [0]                               
                                    [0]                               
                                 >= [0]                               
                                    [0]                               
                                 =  [nil()]                           
                                                                      
                    [mark(s(X))] =  [1 8] X + [9]                     
                                    [0 1]     [2]                     
                                 >  [1 8] X + [7]                     
                                    [0 1]     [2]                     
                                 =  [s(mark(X))]                      
                                                                      
            [mark(cons(X1, X2))] =  [1 1] X1 + [0 2] X2 + [1]         
                                    [0 1]      [0 0]      [1]         
                                 >  [1 1] X1 + [0 2] X2 + [0]         
                                    [0 1]      [0 0]      [1]         
                                 =  [cons(mark(X1), X2)]              
                                                                      
           [mark(first(X1, X2))] =  [1 1] X1 + [1 8] X2 + [1]         
                                    [0 1]      [0 1]      [1]         
                                 >  [1 1] X1 + [1 8] X2 + [0]         
                                    [0 1]      [0 1]      [1]         
                                 =  [a__first(mark(X1), mark(X2))]    
                                                                      
                 [mark(from(X))] =  [1 4] X + [8]                     
                                    [0 1]     [1]                     
                                 >  [1 4] X + [7]                     
                                    [0 1]     [1]                     
                                 =  [a__from(mark(X))]                
                                                                      
                    [a__from(X)] =  [1 3] X + [7]                     
                                    [0 1]     [1]                     
                                 >  [1 3] X + [6]                     
                                    [0 1]     [1]                     
                                 =  [cons(mark(X), from(s(X)))]       
                                                                      
                    [a__from(X)] =  [1 3] X + [7]                     
                                    [0 1]     [1]                     
                                 >= [1 3] X + [7]                     
                                    [0 1]     [1]                     
                                 =  [from(X)]                         
                                                                      

We return to the main proof.

We are left with following problem, upon which TcT provides the
certificate YES(O(1),O(1)).

Weak Trs:
  { a__first(X1, X2) -> first(X1, X2)
  , a__first(0(), X) -> nil()
  , a__first(s(X), cons(Y, Z)) -> cons(mark(Y), first(X, Z))
  , mark(0()) -> 0()
  , mark(nil()) -> nil()
  , mark(s(X)) -> s(mark(X))
  , mark(cons(X1, X2)) -> cons(mark(X1), X2)
  , mark(first(X1, X2)) -> a__first(mark(X1), mark(X2))
  , mark(from(X)) -> a__from(mark(X))
  , a__from(X) -> cons(mark(X), from(s(X)))
  , a__from(X) -> from(X) }
Obligation:
  innermost runtime complexity
Answer:
  YES(O(1),O(1))

Empty rules are trivially bounded

Hurray, we answered YES(O(1),O(n^2))