We consider the following Problem:

  Strict Trs:
    {  __(__(X, Y), Z) -> __(X, __(Y, Z))
     , __(X, nil()) -> X
     , __(nil(), X) -> X
     , U11(tt()) -> U12(tt())
     , U12(tt()) -> tt()
     , isNePal(__(I, __(P, I))) -> U11(tt())
     , activate(X) -> X}
  StartTerms: basic terms
  Strategy: innermost

Certificate: YES(?,O(n^1))

Proof:
  We consider the following Problem:
  
    Strict Trs:
      {  __(__(X, Y), Z) -> __(X, __(Y, Z))
       , __(X, nil()) -> X
       , __(nil(), X) -> X
       , U11(tt()) -> U12(tt())
       , U12(tt()) -> tt()
       , isNePal(__(I, __(P, I))) -> U11(tt())
       , activate(X) -> X}
    StartTerms: basic terms
    Strategy: innermost
  
  Certificate: YES(?,O(n^1))
  
  Proof:
    The weightgap principle applies, where following rules are oriented strictly:
    
    TRS Component: {U12(tt()) -> tt()}
    
    Interpretation of nonconstant growth:
    -------------------------------------
      The following argument positions are usable:
        Uargs(__) = {2}, Uargs(U11) = {}, Uargs(U12) = {},
        Uargs(isNePal) = {}, Uargs(activate) = {}
      We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
      Interpretation Functions:
       __(x1, x2) = [1 0] x1 + [1 0] x2 + [0]
                    [0 1]      [0 0]      [0]
       nil() = [0]
               [0]
       U11(x1) = [0 0] x1 + [1]
                 [0 0]      [1]
       tt() = [0]
              [0]
       U12(x1) = [0 0] x1 + [1]
                 [0 0]      [1]
       isNePal(x1) = [0 0] x1 + [1]
                     [0 0]      [1]
       activate(x1) = [1 0] x1 + [0]
                      [0 0]      [0]
    
    The strictly oriented rules are moved into the weak component.
    
    We consider the following Problem:
    
      Strict Trs:
        {  __(__(X, Y), Z) -> __(X, __(Y, Z))
         , __(X, nil()) -> X
         , __(nil(), X) -> X
         , U11(tt()) -> U12(tt())
         , isNePal(__(I, __(P, I))) -> U11(tt())
         , activate(X) -> X}
      Weak Trs: {U12(tt()) -> tt()}
      StartTerms: basic terms
      Strategy: innermost
    
    Certificate: YES(?,O(n^1))
    
    Proof:
      The weightgap principle applies, where following rules are oriented strictly:
      
      TRS Component: {activate(X) -> X}
      
      Interpretation of nonconstant growth:
      -------------------------------------
        The following argument positions are usable:
          Uargs(__) = {2}, Uargs(U11) = {}, Uargs(U12) = {},
          Uargs(isNePal) = {}, Uargs(activate) = {}
        We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
        Interpretation Functions:
         __(x1, x2) = [1 0] x1 + [1 0] x2 + [0]
                      [0 1]      [0 0]      [0]
         nil() = [0]
                 [0]
         U11(x1) = [0 0] x1 + [1]
                   [0 0]      [1]
         tt() = [0]
                [0]
         U12(x1) = [0 0] x1 + [1]
                   [0 0]      [1]
         isNePal(x1) = [0 0] x1 + [1]
                       [0 0]      [1]
         activate(x1) = [1 0] x1 + [2]
                        [0 1]      [0]
      
      The strictly oriented rules are moved into the weak component.
      
      We consider the following Problem:
      
        Strict Trs:
          {  __(__(X, Y), Z) -> __(X, __(Y, Z))
           , __(X, nil()) -> X
           , __(nil(), X) -> X
           , U11(tt()) -> U12(tt())
           , isNePal(__(I, __(P, I))) -> U11(tt())}
        Weak Trs:
          {  activate(X) -> X
           , U12(tt()) -> tt()}
        StartTerms: basic terms
        Strategy: innermost
      
      Certificate: YES(?,O(n^1))
      
      Proof:
        The weightgap principle applies, where following rules are oriented strictly:
        
        TRS Component: {isNePal(__(I, __(P, I))) -> U11(tt())}
        
        Interpretation of nonconstant growth:
        -------------------------------------
          The following argument positions are usable:
            Uargs(__) = {2}, Uargs(U11) = {}, Uargs(U12) = {},
            Uargs(isNePal) = {}, Uargs(activate) = {}
          We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
          Interpretation Functions:
           __(x1, x2) = [1 0] x1 + [1 0] x2 + [0]
                        [0 1]      [0 0]      [0]
           nil() = [0]
                   [0]
           U11(x1) = [0 0] x1 + [1]
                     [0 0]      [1]
           tt() = [0]
                  [0]
           U12(x1) = [0 0] x1 + [1]
                     [0 0]      [1]
           isNePal(x1) = [0 0] x1 + [3]
                         [0 0]      [1]
           activate(x1) = [1 0] x1 + [0]
                          [0 1]      [0]
        
        The strictly oriented rules are moved into the weak component.
        
        We consider the following Problem:
        
          Strict Trs:
            {  __(__(X, Y), Z) -> __(X, __(Y, Z))
             , __(X, nil()) -> X
             , __(nil(), X) -> X
             , U11(tt()) -> U12(tt())}
          Weak Trs:
            {  isNePal(__(I, __(P, I))) -> U11(tt())
             , activate(X) -> X
             , U12(tt()) -> tt()}
          StartTerms: basic terms
          Strategy: innermost
        
        Certificate: YES(?,O(n^1))
        
        Proof:
          The weightgap principle applies, where following rules are oriented strictly:
          
          TRS Component: {U11(tt()) -> U12(tt())}
          
          Interpretation of nonconstant growth:
          -------------------------------------
            The following argument positions are usable:
              Uargs(__) = {2}, Uargs(U11) = {}, Uargs(U12) = {},
              Uargs(isNePal) = {}, Uargs(activate) = {}
            We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
            Interpretation Functions:
             __(x1, x2) = [1 0] x1 + [1 0] x2 + [0]
                          [0 1]      [0 0]      [0]
             nil() = [0]
                     [0]
             U11(x1) = [0 0] x1 + [1]
                       [0 0]      [1]
             tt() = [0]
                    [0]
             U12(x1) = [0 0] x1 + [0]
                       [0 0]      [1]
             isNePal(x1) = [0 0] x1 + [1]
                           [0 0]      [1]
             activate(x1) = [1 0] x1 + [0]
                            [0 1]      [0]
          
          The strictly oriented rules are moved into the weak component.
          
          We consider the following Problem:
          
            Strict Trs:
              {  __(__(X, Y), Z) -> __(X, __(Y, Z))
               , __(X, nil()) -> X
               , __(nil(), X) -> X}
            Weak Trs:
              {  U11(tt()) -> U12(tt())
               , isNePal(__(I, __(P, I))) -> U11(tt())
               , activate(X) -> X
               , U12(tt()) -> tt()}
            StartTerms: basic terms
            Strategy: innermost
          
          Certificate: YES(?,O(n^1))
          
          Proof:
            The weightgap principle applies, where following rules are oriented strictly:
            
            TRS Component: {__(X, nil()) -> X}
            
            Interpretation of nonconstant growth:
            -------------------------------------
              The following argument positions are usable:
                Uargs(__) = {2}, Uargs(U11) = {}, Uargs(U12) = {},
                Uargs(isNePal) = {}, Uargs(activate) = {}
              We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
              Interpretation Functions:
               __(x1, x2) = [1 0] x1 + [1 0] x2 + [0]
                            [0 1]      [0 0]      [0]
               nil() = [2]
                       [0]
               U11(x1) = [0 0] x1 + [1]
                         [0 0]      [1]
               tt() = [0]
                      [0]
               U12(x1) = [0 0] x1 + [1]
                         [0 0]      [1]
               isNePal(x1) = [0 0] x1 + [1]
                             [0 0]      [1]
               activate(x1) = [1 0] x1 + [0]
                              [0 1]      [0]
            
            The strictly oriented rules are moved into the weak component.
            
            We consider the following Problem:
            
              Strict Trs:
                {  __(__(X, Y), Z) -> __(X, __(Y, Z))
                 , __(nil(), X) -> X}
              Weak Trs:
                {  __(X, nil()) -> X
                 , U11(tt()) -> U12(tt())
                 , isNePal(__(I, __(P, I))) -> U11(tt())
                 , activate(X) -> X
                 , U12(tt()) -> tt()}
              StartTerms: basic terms
              Strategy: innermost
            
            Certificate: YES(?,O(n^1))
            
            Proof:
              The weightgap principle applies, where following rules are oriented strictly:
              
              TRS Component: {__(nil(), X) -> X}
              
              Interpretation of nonconstant growth:
              -------------------------------------
                The following argument positions are usable:
                  Uargs(__) = {2}, Uargs(U11) = {}, Uargs(U12) = {},
                  Uargs(isNePal) = {}, Uargs(activate) = {}
                We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
                Interpretation Functions:
                 __(x1, x2) = [1 0] x1 + [1 0] x2 + [0]
                              [1 1]      [0 1]      [0]
                 nil() = [2]
                         [0]
                 U11(x1) = [1 0] x1 + [1]
                           [1 0]      [1]
                 tt() = [0]
                        [0]
                 U12(x1) = [0 0] x1 + [1]
                           [0 0]      [1]
                 isNePal(x1) = [0 0] x1 + [1]
                               [0 0]      [1]
                 activate(x1) = [1 0] x1 + [0]
                                [0 1]      [0]
              
              The strictly oriented rules are moved into the weak component.
              
              We consider the following Problem:
              
                Strict Trs: {__(__(X, Y), Z) -> __(X, __(Y, Z))}
                Weak Trs:
                  {  __(nil(), X) -> X
                   , __(X, nil()) -> X
                   , U11(tt()) -> U12(tt())
                   , isNePal(__(I, __(P, I))) -> U11(tt())
                   , activate(X) -> X
                   , U12(tt()) -> tt()}
                StartTerms: basic terms
                Strategy: innermost
              
              Certificate: YES(?,O(n^1))
              
              Proof:
                We consider the following Problem:
                
                  Strict Trs: {__(__(X, Y), Z) -> __(X, __(Y, Z))}
                  Weak Trs:
                    {  __(nil(), X) -> X
                     , __(X, nil()) -> X
                     , U11(tt()) -> U12(tt())
                     , isNePal(__(I, __(P, I))) -> U11(tt())
                     , activate(X) -> X
                     , U12(tt()) -> tt()}
                  StartTerms: basic terms
                  Strategy: innermost
                
                Certificate: YES(?,O(n^1))
                
                Proof:
                  The problem is match-bounded by 0.
                  The enriched problem is compatible with the following automaton:
                  {  ___0(2, 2) -> 1
                   , nil_0() -> 1
                   , nil_0() -> 2
                   , U11_0(2) -> 1
                   , tt_0() -> 1
                   , tt_0() -> 2
                   , U12_0(2) -> 1
                   , isNePal_0(2) -> 1
                   , activate_0(2) -> 1}

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