*** 1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__dbl(X)) -> dbl(activate(X))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        add(s(X),Y) -> s(n__add(activate(X),Y))
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        dbl(s(X)) -> s(n__s(n__dbl(activate(X))))
        first(X1,X2) -> n__first(X1,X2)
        first(0(),X) -> nil()
        first(s(X),cons(Y,Z)) -> cons(Y,n__first(activate(X),activate(Z)))
        s(X) -> n__s(X)
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        sqr(s(X)) -> s(n__add(n__sqr(activate(X)),n__dbl(activate(X))))
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
        terms(X) -> n__terms(X)
      Weak DP Rules:
        
      Weak TRS Rules:
        
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      InnermostRuleRemoval
    Proof:
      Arguments of following rules are not normal-forms.
        add(s(X),Y) -> s(n__add(activate(X),Y))
        dbl(s(X)) -> s(n__s(n__dbl(activate(X))))
        first(s(X),cons(Y,Z)) -> cons(Y,n__first(activate(X),activate(Z)))
        sqr(s(X)) -> s(n__add(n__sqr(activate(X)),n__dbl(activate(X))))
      All above mentioned rules can be savely removed.
*** 1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__dbl(X)) -> dbl(activate(X))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(X1,X2) -> n__first(X1,X2)
        first(0(),X) -> nil()
        s(X) -> n__s(X)
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
        terms(X) -> n__terms(X)
      Weak DP Rules:
        
      Weak TRS Rules:
        
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [0]                  
          p(activate) = [2] x1 + [0]         
               p(add) = [1] x1 + [1] x2 + [0]
              p(cons) = [1] x1 + [1] x2 + [0]
               p(dbl) = [1] x1 + [0]         
             p(first) = [1] x1 + [1] x2 + [0]
            p(n__add) = [1] x1 + [1] x2 + [0]
            p(n__dbl) = [1] x1 + [0]         
          p(n__first) = [1] x1 + [1] x2 + [0]
              p(n__s) = [0]                  
            p(n__sqr) = [1] x1 + [0]         
          p(n__terms) = [1] x1 + [0]         
               p(nil) = [0]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [0]                  
               p(sqr) = [1] x1 + [11]        
             p(terms) = [1] x1 + [1]         
        
        Following rules are strictly oriented:
          sqr(X) = [1] X + [11]
                 > [1] X + [0] 
                 = n__sqr(X)   
        
        sqr(0()) = [11]        
                 > [0]         
                 = 0()         
        
        terms(X) = [1] X + [1] 
                 > [1] X + [0] 
                 = n__terms(X) 
        
        
        Following rules are (at-least) weakly oriented:
                      activate(X) =  [2] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
          activate(n__add(X1,X2)) =  [2] X1 + [2] X2 + [0]           
                                  >= [2] X1 + [2] X2 + [0]           
                                  =  add(activate(X1),activate(X2))  
        
              activate(n__dbl(X)) =  [2] X + [0]                     
                                  >= [2] X + [0]                     
                                  =  dbl(activate(X))                
        
        activate(n__first(X1,X2)) =  [2] X1 + [2] X2 + [0]           
                                  >= [2] X1 + [2] X2 + [0]           
                                  =  first(activate(X1),activate(X2))
        
                activate(n__s(X)) =  [0]                             
                                  >= [0]                             
                                  =  s(X)                            
        
              activate(n__sqr(X)) =  [2] X + [0]                     
                                  >= [2] X + [11]                    
                                  =  sqr(activate(X))                
        
            activate(n__terms(X)) =  [2] X + [0]                     
                                  >= [2] X + [1]                     
                                  =  terms(activate(X))              
        
                       add(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [0]           
                                  =  n__add(X1,X2)                   
        
                       add(0(),X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
                           dbl(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__dbl(X)                       
        
                         dbl(0()) =  [0]                             
                                  >= [0]                             
                                  =  0()                             
        
                     first(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [0]           
                                  =  n__first(X1,X2)                 
        
                     first(0(),X) =  [1] X + [0]                     
                                  >= [0]                             
                                  =  nil()                           
        
                             s(X) =  [0]                             
                                  >= [0]                             
                                  =  n__s(X)                         
        
                         terms(N) =  [1] N + [1]                     
                                  >= [1] N + [11]                    
                                  =  cons(recip(sqr(N))              
                                         ,n__terms(n__s(N)))         
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__dbl(X)) -> dbl(activate(X))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(X1,X2) -> n__first(X1,X2)
        first(0(),X) -> nil()
        s(X) -> n__s(X)
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
      Weak DP Rules:
        
      Weak TRS Rules:
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [0]                  
          p(activate) = [8] x1 + [6]         
               p(add) = [1] x1 + [1] x2 + [0]
              p(cons) = [1] x1 + [1] x2 + [0]
               p(dbl) = [1] x1 + [3]         
             p(first) = [1] x1 + [1] x2 + [0]
            p(n__add) = [1] x1 + [1] x2 + [0]
            p(n__dbl) = [1] x1 + [0]         
          p(n__first) = [1] x1 + [1] x2 + [2]
              p(n__s) = [2]                  
            p(n__sqr) = [1] x1 + [0]         
          p(n__terms) = [1] x1 + [3]         
               p(nil) = [0]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [0]                  
               p(sqr) = [1] x1 + [0]         
             p(terms) = [1] x1 + [3]         
        
        Following rules are strictly oriented:
                      activate(X) = [8] X + [6]                     
                                  > [1] X + [0]                     
                                  = X                               
        
        activate(n__first(X1,X2)) = [8] X1 + [8] X2 + [22]          
                                  > [8] X1 + [8] X2 + [12]          
                                  = first(activate(X1),activate(X2))
        
                activate(n__s(X)) = [22]                            
                                  > [0]                             
                                  = s(X)                            
        
            activate(n__terms(X)) = [8] X + [30]                    
                                  > [8] X + [9]                     
                                  = terms(activate(X))              
        
                           dbl(X) = [1] X + [3]                     
                                  > [1] X + [0]                     
                                  = n__dbl(X)                       
        
                         dbl(0()) = [3]                             
                                  > [0]                             
                                  = 0()                             
        
        
        Following rules are (at-least) weakly oriented:
        activate(n__add(X1,X2)) =  [8] X1 + [8] X2 + [6]         
                                >= [8] X1 + [8] X2 + [12]        
                                =  add(activate(X1),activate(X2))
        
            activate(n__dbl(X)) =  [8] X + [6]                   
                                >= [8] X + [9]                   
                                =  dbl(activate(X))              
        
            activate(n__sqr(X)) =  [8] X + [6]                   
                                >= [8] X + [6]                   
                                =  sqr(activate(X))              
        
                     add(X1,X2) =  [1] X1 + [1] X2 + [0]         
                                >= [1] X1 + [1] X2 + [0]         
                                =  n__add(X1,X2)                 
        
                     add(0(),X) =  [1] X + [0]                   
                                >= [1] X + [0]                   
                                =  X                             
        
                   first(X1,X2) =  [1] X1 + [1] X2 + [0]         
                                >= [1] X1 + [1] X2 + [2]         
                                =  n__first(X1,X2)               
        
                   first(0(),X) =  [1] X + [0]                   
                                >= [0]                           
                                =  nil()                         
        
                           s(X) =  [0]                           
                                >= [2]                           
                                =  n__s(X)                       
        
                         sqr(X) =  [1] X + [0]                   
                                >= [1] X + [0]                   
                                =  n__sqr(X)                     
        
                       sqr(0()) =  [0]                           
                                >= [0]                           
                                =  0()                           
        
                       terms(N) =  [1] N + [3]                   
                                >= [1] N + [5]                   
                                =  cons(recip(sqr(N))            
                                       ,n__terms(n__s(N)))       
        
                       terms(X) =  [1] X + [3]                   
                                >= [1] X + [3]                   
                                =  n__terms(X)                   
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__dbl(X)) -> dbl(activate(X))
        activate(n__sqr(X)) -> sqr(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        first(X1,X2) -> n__first(X1,X2)
        first(0(),X) -> nil()
        s(X) -> n__s(X)
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
      Weak DP Rules:
        
      Weak TRS Rules:
        activate(X) -> X
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__terms(X)) -> terms(activate(X))
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [2]                  
          p(activate) = [2] x1 + [0]         
               p(add) = [1] x1 + [1] x2 + [7]
              p(cons) = [1] x1 + [0]         
               p(dbl) = [1] x1 + [2]         
             p(first) = [1] x1 + [1] x2 + [0]
            p(n__add) = [1] x1 + [1] x2 + [4]
            p(n__dbl) = [1] x1 + [0]         
          p(n__first) = [1] x1 + [1] x2 + [4]
              p(n__s) = [0]                  
            p(n__sqr) = [1] x1 + [0]         
          p(n__terms) = [1] x1 + [0]         
               p(nil) = [0]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [0]                  
               p(sqr) = [1] x1 + [0]         
             p(terms) = [1] x1 + [0]         
        
        Following rules are strictly oriented:
        activate(n__add(X1,X2)) = [2] X1 + [2] X2 + [8]         
                                > [2] X1 + [2] X2 + [7]         
                                = add(activate(X1),activate(X2))
        
                     add(X1,X2) = [1] X1 + [1] X2 + [7]         
                                > [1] X1 + [1] X2 + [4]         
                                = n__add(X1,X2)                 
        
                     add(0(),X) = [1] X + [9]                   
                                > [1] X + [0]                   
                                = X                             
        
                   first(0(),X) = [1] X + [2]                   
                                > [0]                           
                                = nil()                         
        
        
        Following rules are (at-least) weakly oriented:
                      activate(X) =  [2] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
              activate(n__dbl(X)) =  [2] X + [0]                     
                                  >= [2] X + [2]                     
                                  =  dbl(activate(X))                
        
        activate(n__first(X1,X2)) =  [2] X1 + [2] X2 + [8]           
                                  >= [2] X1 + [2] X2 + [0]           
                                  =  first(activate(X1),activate(X2))
        
                activate(n__s(X)) =  [0]                             
                                  >= [0]                             
                                  =  s(X)                            
        
              activate(n__sqr(X)) =  [2] X + [0]                     
                                  >= [2] X + [0]                     
                                  =  sqr(activate(X))                
        
            activate(n__terms(X)) =  [2] X + [0]                     
                                  >= [2] X + [0]                     
                                  =  terms(activate(X))              
        
                           dbl(X) =  [1] X + [2]                     
                                  >= [1] X + [0]                     
                                  =  n__dbl(X)                       
        
                         dbl(0()) =  [4]                             
                                  >= [2]                             
                                  =  0()                             
        
                     first(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [4]           
                                  =  n__first(X1,X2)                 
        
                             s(X) =  [0]                             
                                  >= [0]                             
                                  =  n__s(X)                         
        
                           sqr(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__sqr(X)                       
        
                         sqr(0()) =  [2]                             
                                  >= [2]                             
                                  =  0()                             
        
                         terms(N) =  [1] N + [0]                     
                                  >= [1] N + [0]                     
                                  =  cons(recip(sqr(N))              
                                         ,n__terms(n__s(N)))         
        
                         terms(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__terms(X)                     
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1.1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(n__dbl(X)) -> dbl(activate(X))
        activate(n__sqr(X)) -> sqr(activate(X))
        first(X1,X2) -> n__first(X1,X2)
        s(X) -> n__s(X)
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
      Weak DP Rules:
        
      Weak TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(0(),X) -> nil()
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [1]                  
          p(activate) = [4] x1 + [0]         
               p(add) = [1] x1 + [1] x2 + [6]
              p(cons) = [1] x1 + [1] x2 + [0]
               p(dbl) = [1] x1 + [0]         
             p(first) = [1] x1 + [1] x2 + [0]
            p(n__add) = [1] x1 + [1] x2 + [3]
            p(n__dbl) = [1] x1 + [0]         
          p(n__first) = [1] x1 + [1] x2 + [2]
              p(n__s) = [1]                  
            p(n__sqr) = [1] x1 + [1]         
          p(n__terms) = [1] x1 + [0]         
               p(nil) = [1]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [1]                  
               p(sqr) = [1] x1 + [1]         
             p(terms) = [1] x1 + [0]         
        
        Following rules are strictly oriented:
        activate(n__sqr(X)) = [4] X + [4]     
                            > [4] X + [1]     
                            = sqr(activate(X))
        
        
        Following rules are (at-least) weakly oriented:
                      activate(X) =  [4] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
          activate(n__add(X1,X2)) =  [4] X1 + [4] X2 + [12]          
                                  >= [4] X1 + [4] X2 + [6]           
                                  =  add(activate(X1),activate(X2))  
        
              activate(n__dbl(X)) =  [4] X + [0]                     
                                  >= [4] X + [0]                     
                                  =  dbl(activate(X))                
        
        activate(n__first(X1,X2)) =  [4] X1 + [4] X2 + [8]           
                                  >= [4] X1 + [4] X2 + [0]           
                                  =  first(activate(X1),activate(X2))
        
                activate(n__s(X)) =  [4]                             
                                  >= [1]                             
                                  =  s(X)                            
        
            activate(n__terms(X)) =  [4] X + [0]                     
                                  >= [4] X + [0]                     
                                  =  terms(activate(X))              
        
                       add(X1,X2) =  [1] X1 + [1] X2 + [6]           
                                  >= [1] X1 + [1] X2 + [3]           
                                  =  n__add(X1,X2)                   
        
                       add(0(),X) =  [1] X + [7]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
                           dbl(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__dbl(X)                       
        
                         dbl(0()) =  [1]                             
                                  >= [1]                             
                                  =  0()                             
        
                     first(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [2]           
                                  =  n__first(X1,X2)                 
        
                     first(0(),X) =  [1] X + [1]                     
                                  >= [1]                             
                                  =  nil()                           
        
                             s(X) =  [1]                             
                                  >= [1]                             
                                  =  n__s(X)                         
        
                           sqr(X) =  [1] X + [1]                     
                                  >= [1] X + [1]                     
                                  =  n__sqr(X)                       
        
                         sqr(0()) =  [2]                             
                                  >= [1]                             
                                  =  0()                             
        
                         terms(N) =  [1] N + [0]                     
                                  >= [1] N + [2]                     
                                  =  cons(recip(sqr(N))              
                                         ,n__terms(n__s(N)))         
        
                         terms(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__terms(X)                     
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1.1.1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(n__dbl(X)) -> dbl(activate(X))
        first(X1,X2) -> n__first(X1,X2)
        s(X) -> n__s(X)
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
      Weak DP Rules:
        
      Weak TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(0(),X) -> nil()
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [0]                  
          p(activate) = [4] x1 + [0]         
               p(add) = [1] x1 + [1] x2 + [1]
              p(cons) = [1] x1 + [0]         
               p(dbl) = [1] x1 + [0]         
             p(first) = [1] x1 + [1] x2 + [0]
            p(n__add) = [1] x1 + [1] x2 + [1]
            p(n__dbl) = [1] x1 + [0]         
          p(n__first) = [1] x1 + [1] x2 + [0]
              p(n__s) = [1] x1 + [0]         
            p(n__sqr) = [1] x1 + [0]         
          p(n__terms) = [1] x1 + [2]         
               p(nil) = [0]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [4] x1 + [0]         
               p(sqr) = [1] x1 + [0]         
             p(terms) = [1] x1 + [3]         
        
        Following rules are strictly oriented:
        terms(N) = [1] N + [3]            
                 > [1] N + [0]            
                 = cons(recip(sqr(N))     
                       ,n__terms(n__s(N)))
        
        
        Following rules are (at-least) weakly oriented:
                      activate(X) =  [4] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
          activate(n__add(X1,X2)) =  [4] X1 + [4] X2 + [4]           
                                  >= [4] X1 + [4] X2 + [1]           
                                  =  add(activate(X1),activate(X2))  
        
              activate(n__dbl(X)) =  [4] X + [0]                     
                                  >= [4] X + [0]                     
                                  =  dbl(activate(X))                
        
        activate(n__first(X1,X2)) =  [4] X1 + [4] X2 + [0]           
                                  >= [4] X1 + [4] X2 + [0]           
                                  =  first(activate(X1),activate(X2))
        
                activate(n__s(X)) =  [4] X + [0]                     
                                  >= [4] X + [0]                     
                                  =  s(X)                            
        
              activate(n__sqr(X)) =  [4] X + [0]                     
                                  >= [4] X + [0]                     
                                  =  sqr(activate(X))                
        
            activate(n__terms(X)) =  [4] X + [8]                     
                                  >= [4] X + [3]                     
                                  =  terms(activate(X))              
        
                       add(X1,X2) =  [1] X1 + [1] X2 + [1]           
                                  >= [1] X1 + [1] X2 + [1]           
                                  =  n__add(X1,X2)                   
        
                       add(0(),X) =  [1] X + [1]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
                           dbl(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__dbl(X)                       
        
                         dbl(0()) =  [0]                             
                                  >= [0]                             
                                  =  0()                             
        
                     first(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [0]           
                                  =  n__first(X1,X2)                 
        
                     first(0(),X) =  [1] X + [0]                     
                                  >= [0]                             
                                  =  nil()                           
        
                             s(X) =  [4] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__s(X)                         
        
                           sqr(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__sqr(X)                       
        
                         sqr(0()) =  [0]                             
                                  >= [0]                             
                                  =  0()                             
        
                         terms(X) =  [1] X + [3]                     
                                  >= [1] X + [2]                     
                                  =  n__terms(X)                     
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1.1.1.1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(n__dbl(X)) -> dbl(activate(X))
        first(X1,X2) -> n__first(X1,X2)
        s(X) -> n__s(X)
      Weak DP Rules:
        
      Weak TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(0(),X) -> nil()
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [0]                  
          p(activate) = [4] x1 + [0]         
               p(add) = [1] x1 + [1] x2 + [0]
              p(cons) = [1] x1 + [4]         
               p(dbl) = [1] x1 + [1]         
             p(first) = [1] x1 + [1] x2 + [0]
            p(n__add) = [1] x1 + [1] x2 + [0]
            p(n__dbl) = [1] x1 + [0]         
          p(n__first) = [1] x1 + [1] x2 + [0]
              p(n__s) = [2]                  
            p(n__sqr) = [1] x1 + [0]         
          p(n__terms) = [1] x1 + [1]         
               p(nil) = [0]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [3]                  
               p(sqr) = [1] x1 + [0]         
             p(terms) = [1] x1 + [4]         
        
        Following rules are strictly oriented:
        s(X) = [3]    
             > [2]    
             = n__s(X)
        
        
        Following rules are (at-least) weakly oriented:
                      activate(X) =  [4] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
          activate(n__add(X1,X2)) =  [4] X1 + [4] X2 + [0]           
                                  >= [4] X1 + [4] X2 + [0]           
                                  =  add(activate(X1),activate(X2))  
        
              activate(n__dbl(X)) =  [4] X + [0]                     
                                  >= [4] X + [1]                     
                                  =  dbl(activate(X))                
        
        activate(n__first(X1,X2)) =  [4] X1 + [4] X2 + [0]           
                                  >= [4] X1 + [4] X2 + [0]           
                                  =  first(activate(X1),activate(X2))
        
                activate(n__s(X)) =  [8]                             
                                  >= [3]                             
                                  =  s(X)                            
        
              activate(n__sqr(X)) =  [4] X + [0]                     
                                  >= [4] X + [0]                     
                                  =  sqr(activate(X))                
        
            activate(n__terms(X)) =  [4] X + [4]                     
                                  >= [4] X + [4]                     
                                  =  terms(activate(X))              
        
                       add(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [0]           
                                  =  n__add(X1,X2)                   
        
                       add(0(),X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
                           dbl(X) =  [1] X + [1]                     
                                  >= [1] X + [0]                     
                                  =  n__dbl(X)                       
        
                         dbl(0()) =  [1]                             
                                  >= [0]                             
                                  =  0()                             
        
                     first(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [0]           
                                  =  n__first(X1,X2)                 
        
                     first(0(),X) =  [1] X + [0]                     
                                  >= [0]                             
                                  =  nil()                           
        
                           sqr(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__sqr(X)                       
        
                         sqr(0()) =  [0]                             
                                  >= [0]                             
                                  =  0()                             
        
                         terms(N) =  [1] N + [4]                     
                                  >= [1] N + [4]                     
                                  =  cons(recip(sqr(N))              
                                         ,n__terms(n__s(N)))         
        
                         terms(X) =  [1] X + [4]                     
                                  >= [1] X + [1]                     
                                  =  n__terms(X)                     
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1.1.1.1.1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(n__dbl(X)) -> dbl(activate(X))
        first(X1,X2) -> n__first(X1,X2)
      Weak DP Rules:
        
      Weak TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(0(),X) -> nil()
        s(X) -> n__s(X)
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [0]                  
          p(activate) = [5] x1 + [0]         
               p(add) = [1] x1 + [1] x2 + [0]
              p(cons) = [1] x1 + [1] x2 + [0]
               p(dbl) = [1] x1 + [0]         
             p(first) = [1] x1 + [1] x2 + [5]
            p(n__add) = [1] x1 + [1] x2 + [0]
            p(n__dbl) = [1] x1 + [0]         
          p(n__first) = [1] x1 + [1] x2 + [1]
              p(n__s) = [0]                  
            p(n__sqr) = [1] x1 + [0]         
          p(n__terms) = [1] x1 + [0]         
               p(nil) = [5]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [0]                  
               p(sqr) = [1] x1 + [0]         
             p(terms) = [1] x1 + [0]         
        
        Following rules are strictly oriented:
        first(X1,X2) = [1] X1 + [1] X2 + [5]
                     > [1] X1 + [1] X2 + [1]
                     = n__first(X1,X2)      
        
        
        Following rules are (at-least) weakly oriented:
                      activate(X) =  [5] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
          activate(n__add(X1,X2)) =  [5] X1 + [5] X2 + [0]           
                                  >= [5] X1 + [5] X2 + [0]           
                                  =  add(activate(X1),activate(X2))  
        
              activate(n__dbl(X)) =  [5] X + [0]                     
                                  >= [5] X + [0]                     
                                  =  dbl(activate(X))                
        
        activate(n__first(X1,X2)) =  [5] X1 + [5] X2 + [5]           
                                  >= [5] X1 + [5] X2 + [5]           
                                  =  first(activate(X1),activate(X2))
        
                activate(n__s(X)) =  [0]                             
                                  >= [0]                             
                                  =  s(X)                            
        
              activate(n__sqr(X)) =  [5] X + [0]                     
                                  >= [5] X + [0]                     
                                  =  sqr(activate(X))                
        
            activate(n__terms(X)) =  [5] X + [0]                     
                                  >= [5] X + [0]                     
                                  =  terms(activate(X))              
        
                       add(X1,X2) =  [1] X1 + [1] X2 + [0]           
                                  >= [1] X1 + [1] X2 + [0]           
                                  =  n__add(X1,X2)                   
        
                       add(0(),X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
                           dbl(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__dbl(X)                       
        
                         dbl(0()) =  [0]                             
                                  >= [0]                             
                                  =  0()                             
        
                     first(0(),X) =  [1] X + [5]                     
                                  >= [5]                             
                                  =  nil()                           
        
                             s(X) =  [0]                             
                                  >= [0]                             
                                  =  n__s(X)                         
        
                           sqr(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__sqr(X)                       
        
                         sqr(0()) =  [0]                             
                                  >= [0]                             
                                  =  0()                             
        
                         terms(N) =  [1] N + [0]                     
                                  >= [1] N + [0]                     
                                  =  cons(recip(sqr(N))              
                                         ,n__terms(n__s(N)))         
        
                         terms(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__terms(X)                     
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1.1.1.1.1.1.1 Progress [(O(1),O(n^1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        activate(n__dbl(X)) -> dbl(activate(X))
      Weak DP Rules:
        
      Weak TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(X1,X2) -> n__first(X1,X2)
        first(0(),X) -> nil()
        s(X) -> n__s(X)
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      WeightGap {wgDimension = 1, wgDegree = 1, wgKind = Algebraic, wgUArgs = UArgs, wgOn = WgOnAny}
    Proof:
      The weightgap principle applies using the following nonconstant growth matrix-interpretation:
        We apply a matrix interpretation of kind constructor based matrix interpretation:
        The following argument positions are considered usable:
          uargs(add) = {1,2},
          uargs(cons) = {1},
          uargs(dbl) = {1},
          uargs(first) = {1,2},
          uargs(recip) = {1},
          uargs(sqr) = {1},
          uargs(terms) = {1}
        
        Following symbols are considered usable:
          {}
        TcT has computed the following interpretation:
                 p(0) = [0]                  
          p(activate) = [4] x1 + [0]         
               p(add) = [1] x1 + [1] x2 + [5]
              p(cons) = [1] x1 + [1] x2 + [0]
               p(dbl) = [1] x1 + [2]         
             p(first) = [1] x1 + [1] x2 + [1]
            p(n__add) = [1] x1 + [1] x2 + [2]
            p(n__dbl) = [1] x1 + [2]         
          p(n__first) = [1] x1 + [1] x2 + [1]
              p(n__s) = [1]                  
            p(n__sqr) = [1] x1 + [0]         
          p(n__terms) = [1] x1 + [1]         
               p(nil) = [0]                  
             p(recip) = [1] x1 + [0]         
                 p(s) = [4]                  
               p(sqr) = [1] x1 + [0]         
             p(terms) = [1] x1 + [2]         
        
        Following rules are strictly oriented:
        activate(n__dbl(X)) = [4] X + [8]     
                            > [4] X + [2]     
                            = dbl(activate(X))
        
        
        Following rules are (at-least) weakly oriented:
                      activate(X) =  [4] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
          activate(n__add(X1,X2)) =  [4] X1 + [4] X2 + [8]           
                                  >= [4] X1 + [4] X2 + [5]           
                                  =  add(activate(X1),activate(X2))  
        
        activate(n__first(X1,X2)) =  [4] X1 + [4] X2 + [4]           
                                  >= [4] X1 + [4] X2 + [1]           
                                  =  first(activate(X1),activate(X2))
        
                activate(n__s(X)) =  [4]                             
                                  >= [4]                             
                                  =  s(X)                            
        
              activate(n__sqr(X)) =  [4] X + [0]                     
                                  >= [4] X + [0]                     
                                  =  sqr(activate(X))                
        
            activate(n__terms(X)) =  [4] X + [4]                     
                                  >= [4] X + [2]                     
                                  =  terms(activate(X))              
        
                       add(X1,X2) =  [1] X1 + [1] X2 + [5]           
                                  >= [1] X1 + [1] X2 + [2]           
                                  =  n__add(X1,X2)                   
        
                       add(0(),X) =  [1] X + [5]                     
                                  >= [1] X + [0]                     
                                  =  X                               
        
                           dbl(X) =  [1] X + [2]                     
                                  >= [1] X + [2]                     
                                  =  n__dbl(X)                       
        
                         dbl(0()) =  [2]                             
                                  >= [0]                             
                                  =  0()                             
        
                     first(X1,X2) =  [1] X1 + [1] X2 + [1]           
                                  >= [1] X1 + [1] X2 + [1]           
                                  =  n__first(X1,X2)                 
        
                     first(0(),X) =  [1] X + [1]                     
                                  >= [0]                             
                                  =  nil()                           
        
                             s(X) =  [4]                             
                                  >= [1]                             
                                  =  n__s(X)                         
        
                           sqr(X) =  [1] X + [0]                     
                                  >= [1] X + [0]                     
                                  =  n__sqr(X)                       
        
                         sqr(0()) =  [0]                             
                                  >= [0]                             
                                  =  0()                             
        
                         terms(N) =  [1] N + [2]                     
                                  >= [1] N + [2]                     
                                  =  cons(recip(sqr(N))              
                                         ,n__terms(n__s(N)))         
        
                         terms(X) =  [1] X + [2]                     
                                  >= [1] X + [1]                     
                                  =  n__terms(X)                     
        
      Further, it can be verified that all rules not oriented are covered by the weightgap condition.
*** 1.1.1.1.1.1.1.1.1.1 Progress [(O(1),O(1))]  ***
    Considered Problem:
      Strict DP Rules:
        
      Strict TRS Rules:
        
      Weak DP Rules:
        
      Weak TRS Rules:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
        activate(n__dbl(X)) -> dbl(activate(X))
        activate(n__first(X1,X2)) -> first(activate(X1),activate(X2))
        activate(n__s(X)) -> s(X)
        activate(n__sqr(X)) -> sqr(activate(X))
        activate(n__terms(X)) -> terms(activate(X))
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        dbl(X) -> n__dbl(X)
        dbl(0()) -> 0()
        first(X1,X2) -> n__first(X1,X2)
        first(0(),X) -> nil()
        s(X) -> n__s(X)
        sqr(X) -> n__sqr(X)
        sqr(0()) -> 0()
        terms(N) -> cons(recip(sqr(N)),n__terms(n__s(N)))
        terms(X) -> n__terms(X)
      Signature:
        {activate/1,add/2,dbl/1,first/2,s/1,sqr/1,terms/1} / {0/0,cons/2,n__add/2,n__dbl/1,n__first/2,n__s/1,n__sqr/1,n__terms/1,nil/0,recip/1}
      Obligation:
        Innermost
        basic terms: {activate,add,dbl,first,s,sqr,terms}/{0,cons,n__add,n__dbl,n__first,n__s,n__sqr,n__terms,nil,recip}
    Applied Processor:
      EmptyProcessor
    Proof:
      The problem is already closed. The intended complexity is O(1).