We consider the following Problem:

  Strict Trs:
    {  eq(0(), 0()) -> true()
     , eq(0(), s(X)) -> false()
     , eq(s(X), 0()) -> false()
     , eq(s(X), s(Y)) -> eq(X, Y)
     , rm(N, nil()) -> nil()
     , rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))
     , ifrm(true(), N, add(M, X)) -> rm(N, X)
     , ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
     , purge(nil()) -> nil()
     , purge(add(N, X)) -> add(N, purge(rm(N, X)))}
  StartTerms: basic terms
  Strategy: innermost

Certificate: YES(?,O(n^2))

Proof:
  We consider the following Problem:
  
    Strict Trs:
      {  eq(0(), 0()) -> true()
       , eq(0(), s(X)) -> false()
       , eq(s(X), 0()) -> false()
       , eq(s(X), s(Y)) -> eq(X, Y)
       , rm(N, nil()) -> nil()
       , rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))
       , ifrm(true(), N, add(M, X)) -> rm(N, X)
       , ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
       , purge(nil()) -> nil()
       , purge(add(N, X)) -> add(N, purge(rm(N, X)))}
    StartTerms: basic terms
    Strategy: innermost
  
  Certificate: YES(?,O(n^2))
  
  Proof:
    The weightgap principle applies, where following rules are oriented strictly:
    
    TRS Component:
      {  eq(0(), 0()) -> true()
       , eq(0(), s(X)) -> false()
       , eq(s(X), 0()) -> false()
       , rm(N, nil()) -> nil()
       , purge(nil()) -> nil()}
    
    Interpretation of nonconstant growth:
    -------------------------------------
      The following argument positions are usable:
        Uargs(eq) = {}, Uargs(s) = {}, Uargs(rm) = {}, Uargs(add) = {2},
        Uargs(ifrm) = {1}, Uargs(purge) = {1}
      We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
      Interpretation Functions:
       eq(x1, x2) = [0 0] x1 + [0 0] x2 + [1]
                    [0 0]      [0 0]      [1]
       0() = [0]
             [0]
       true() = [0]
                [0]
       s(x1) = [0 0] x1 + [0]
               [0 0]      [0]
       false() = [0]
                 [0]
       rm(x1, x2) = [1 1] x1 + [0 0] x2 + [1]
                    [0 0]      [0 0]      [1]
       nil() = [0]
               [0]
       add(x1, x2) = [0 0] x1 + [1 0] x2 + [0]
                     [1 1]      [0 0]      [1]
       ifrm(x1, x2, x3) = [1 0] x1 + [1 1] x2 + [0 0] x3 + [0]
                          [0 0]      [0 0]      [0 0]      [1]
       purge(x1) = [1 1] x1 + [1]
                   [0 0]      [1]
    
    The strictly oriented rules are moved into the weak component.
    
    We consider the following Problem:
    
      Strict Trs:
        {  eq(s(X), s(Y)) -> eq(X, Y)
         , rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))
         , ifrm(true(), N, add(M, X)) -> rm(N, X)
         , ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
         , purge(add(N, X)) -> add(N, purge(rm(N, X)))}
      Weak Trs:
        {  eq(0(), 0()) -> true()
         , eq(0(), s(X)) -> false()
         , eq(s(X), 0()) -> false()
         , rm(N, nil()) -> nil()
         , purge(nil()) -> nil()}
      StartTerms: basic terms
      Strategy: innermost
    
    Certificate: YES(?,O(n^2))
    
    Proof:
      The weightgap principle applies, where following rules are oriented strictly:
      
      TRS Component: {ifrm(true(), N, add(M, X)) -> rm(N, X)}
      
      Interpretation of nonconstant growth:
      -------------------------------------
        The following argument positions are usable:
          Uargs(eq) = {}, Uargs(s) = {}, Uargs(rm) = {}, Uargs(add) = {2},
          Uargs(ifrm) = {1}, Uargs(purge) = {1}
        We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
        Interpretation Functions:
         eq(x1, x2) = [0 0] x1 + [0 0] x2 + [1]
                      [0 0]      [0 0]      [1]
         0() = [0]
               [0]
         true() = [0]
                  [0]
         s(x1) = [0 0] x1 + [0]
                 [0 0]      [0]
         false() = [0]
                   [0]
         rm(x1, x2) = [1 1] x1 + [0 0] x2 + [1]
                      [0 0]      [0 0]      [1]
         nil() = [0]
                 [0]
         add(x1, x2) = [0 0] x1 + [1 0] x2 + [0]
                       [1 1]      [0 0]      [1]
         ifrm(x1, x2, x3) = [1 0] x1 + [1 1] x2 + [0 0] x3 + [2]
                            [0 0]      [0 0]      [0 0]      [1]
         purge(x1) = [1 1] x1 + [0]
                     [0 0]      [1]
      
      The strictly oriented rules are moved into the weak component.
      
      We consider the following Problem:
      
        Strict Trs:
          {  eq(s(X), s(Y)) -> eq(X, Y)
           , rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))
           , ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
           , purge(add(N, X)) -> add(N, purge(rm(N, X)))}
        Weak Trs:
          {  ifrm(true(), N, add(M, X)) -> rm(N, X)
           , eq(0(), 0()) -> true()
           , eq(0(), s(X)) -> false()
           , eq(s(X), 0()) -> false()
           , rm(N, nil()) -> nil()
           , purge(nil()) -> nil()}
        StartTerms: basic terms
        Strategy: innermost
      
      Certificate: YES(?,O(n^2))
      
      Proof:
        The weightgap principle applies, where following rules are oriented strictly:
        
        TRS Component: {ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))}
        
        Interpretation of nonconstant growth:
        -------------------------------------
          The following argument positions are usable:
            Uargs(eq) = {}, Uargs(s) = {}, Uargs(rm) = {}, Uargs(add) = {2},
            Uargs(ifrm) = {1}, Uargs(purge) = {1}
          We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
          Interpretation Functions:
           eq(x1, x2) = [0 0] x1 + [0 0] x2 + [1]
                        [0 0]      [1 0]      [1]
           0() = [3]
                 [0]
           true() = [0]
                    [0]
           s(x1) = [0 0] x1 + [0]
                   [0 0]      [0]
           false() = [1]
                     [0]
           rm(x1, x2) = [1 1] x1 + [0 0] x2 + [0]
                        [0 0]      [0 0]      [1]
           nil() = [0]
                   [0]
           add(x1, x2) = [0 0] x1 + [1 0] x2 + [0]
                         [1 1]      [0 0]      [0]
           ifrm(x1, x2, x3) = [1 0] x1 + [1 1] x2 + [0 0] x3 + [0]
                              [0 0]      [0 0]      [0 1]      [1]
           purge(x1) = [1 1] x1 + [1]
                       [0 0]      [1]
        
        The strictly oriented rules are moved into the weak component.
        
        We consider the following Problem:
        
          Strict Trs:
            {  eq(s(X), s(Y)) -> eq(X, Y)
             , rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))
             , purge(add(N, X)) -> add(N, purge(rm(N, X)))}
          Weak Trs:
            {  ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
             , ifrm(true(), N, add(M, X)) -> rm(N, X)
             , eq(0(), 0()) -> true()
             , eq(0(), s(X)) -> false()
             , eq(s(X), 0()) -> false()
             , rm(N, nil()) -> nil()
             , purge(nil()) -> nil()}
          StartTerms: basic terms
          Strategy: innermost
        
        Certificate: YES(?,O(n^2))
        
        Proof:
          The weightgap principle applies, where following rules are oriented strictly:
          
          TRS Component: {purge(add(N, X)) -> add(N, purge(rm(N, X)))}
          
          Interpretation of nonconstant growth:
          -------------------------------------
            The following argument positions are usable:
              Uargs(eq) = {}, Uargs(s) = {}, Uargs(rm) = {}, Uargs(add) = {2},
              Uargs(ifrm) = {1}, Uargs(purge) = {1}
            We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
            Interpretation Functions:
             eq(x1, x2) = [0 0] x1 + [0 0] x2 + [1]
                          [0 0]      [0 0]      [0]
             0() = [0]
                   [0]
             true() = [0]
                      [0]
             s(x1) = [0 0] x1 + [0]
                     [0 0]      [0]
             false() = [0]
                       [0]
             rm(x1, x2) = [0 0] x1 + [0 0] x2 + [0]
                          [0 0]      [0 0]      [0]
             nil() = [0]
                     [0]
             add(x1, x2) = [0 0] x1 + [1 0] x2 + [0]
                           [0 0]      [0 0]      [1]
             ifrm(x1, x2, x3) = [1 0] x1 + [0 0] x2 + [0 0] x3 + [3]
                                [0 0]      [0 0]      [0 0]      [1]
             purge(x1) = [1 1] x1 + [0]
                         [0 0]      [2]
          
          The strictly oriented rules are moved into the weak component.
          
          We consider the following Problem:
          
            Strict Trs:
              {  eq(s(X), s(Y)) -> eq(X, Y)
               , rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))}
            Weak Trs:
              {  purge(add(N, X)) -> add(N, purge(rm(N, X)))
               , ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
               , ifrm(true(), N, add(M, X)) -> rm(N, X)
               , eq(0(), 0()) -> true()
               , eq(0(), s(X)) -> false()
               , eq(s(X), 0()) -> false()
               , rm(N, nil()) -> nil()
               , purge(nil()) -> nil()}
            StartTerms: basic terms
            Strategy: innermost
          
          Certificate: YES(?,O(n^2))
          
          Proof:
            The weightgap principle applies, where following rules are oriented strictly:
            
            TRS Component: {eq(s(X), s(Y)) -> eq(X, Y)}
            
            Interpretation of nonconstant growth:
            -------------------------------------
              The following argument positions are usable:
                Uargs(eq) = {}, Uargs(s) = {}, Uargs(rm) = {}, Uargs(add) = {2},
                Uargs(ifrm) = {1}, Uargs(purge) = {1}
              We have the following EDA-non-satisfying and IDA(1)-non-satisfying matrix interpretation:
              Interpretation Functions:
               eq(x1, x2) = [0 0] x1 + [0 2] x2 + [0]
                            [0 1]      [0 0]      [2]
               0() = [0]
                     [2]
               true() = [0]
                        [0]
               s(x1) = [0 0] x1 + [0]
                       [0 1]      [2]
               false() = [0]
                         [0]
               rm(x1, x2) = [0 0] x1 + [1 2] x2 + [0]
                            [0 0]      [0 0]      [0]
               nil() = [0]
                       [0]
               add(x1, x2) = [0 0] x1 + [1 2] x2 + [0]
                             [0 1]      [0 0]      [0]
               ifrm(x1, x2, x3) = [1 0] x1 + [0 0] x2 + [1 0] x3 + [0]
                                  [0 0]      [0 0]      [0 1]      [1]
               purge(x1) = [1 0] x1 + [1]
                           [0 1]      [0]
            
            The strictly oriented rules are moved into the weak component.
            
            We consider the following Problem:
            
              Strict Trs: {rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))}
              Weak Trs:
                {  eq(s(X), s(Y)) -> eq(X, Y)
                 , purge(add(N, X)) -> add(N, purge(rm(N, X)))
                 , ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
                 , ifrm(true(), N, add(M, X)) -> rm(N, X)
                 , eq(0(), 0()) -> true()
                 , eq(0(), s(X)) -> false()
                 , eq(s(X), 0()) -> false()
                 , rm(N, nil()) -> nil()
                 , purge(nil()) -> nil()}
              StartTerms: basic terms
              Strategy: innermost
            
            Certificate: YES(?,O(n^2))
            
            Proof:
              We consider the following Problem:
              
                Strict Trs: {rm(N, add(M, X)) -> ifrm(eq(N, M), N, add(M, X))}
                Weak Trs:
                  {  eq(s(X), s(Y)) -> eq(X, Y)
                   , purge(add(N, X)) -> add(N, purge(rm(N, X)))
                   , ifrm(false(), N, add(M, X)) -> add(M, rm(N, X))
                   , ifrm(true(), N, add(M, X)) -> rm(N, X)
                   , eq(0(), 0()) -> true()
                   , eq(0(), s(X)) -> false()
                   , eq(s(X), 0()) -> false()
                   , rm(N, nil()) -> nil()
                   , purge(nil()) -> nil()}
                StartTerms: basic terms
                Strategy: innermost
              
              Certificate: YES(?,O(n^2))
              
              Proof:
                The following argument positions are usable:
                  Uargs(eq) = {}, Uargs(s) = {}, Uargs(rm) = {}, Uargs(add) = {2},
                  Uargs(ifrm) = {1}, Uargs(purge) = {1}
                We have the following constructor-based EDA-non-satisfying and IDA(2)-non-satisfying matrix interpretation:
                Interpretation Functions:
                 eq(x1, x2) = [0 0 0] x1 + [0 0 0] x2 + [0]
                              [0 0 0]      [0 0 0]      [0]
                              [0 0 0]      [0 0 0]      [0]
                 0() = [0]
                       [0]
                       [0]
                 true() = [0]
                          [0]
                          [0]
                 s(x1) = [1 0 0] x1 + [0]
                         [0 1 0]      [0]
                         [0 0 0]      [0]
                 false() = [0]
                           [0]
                           [0]
                 rm(x1, x2) = [0 0 0] x1 + [1 1 0] x2 + [1]
                              [0 0 0]      [0 1 0]      [0]
                              [0 0 0]      [0 0 0]      [0]
                 nil() = [1]
                         [0]
                         [0]
                 add(x1, x2) = [0 0 0] x1 + [1 2 0] x2 + [2]
                               [0 0 0]      [0 1 0]      [2]
                               [0 0 0]      [0 0 0]      [0]
                 ifrm(x1, x2, x3) = [2 0 0] x1 + [0 0 0] x2 + [1 1 0] x3 + [0]
                                    [0 0 0]      [0 0 0]      [0 1 0]      [0]
                                    [0 0 0]      [0 0 0]      [0 0 0]      [0]
                 purge(x1) = [2 0 0] x1 + [2]
                             [0 1 1]      [0]
                             [0 0 0]      [1]

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