0.00/0.01 YES 0.00/0.01 We consider the system theBenchmark. 0.00/0.01 0.00/0.01 Alphabet: 0.00/0.01 0.00/0.01 a : [] --> N 0.00/0.01 f : [N] --> N 0.00/0.01 0.00/0.01 Rules: 0.00/0.01 0.00/0.01 g a => f(a) 0.00/0.01 0.00/0.01 Using the transformations described in [Kop11], this system can be brought in a form without leading free variables in the left-hand side, and where the left-hand side of a variable is always a functional term or application headed by a functional term. 0.00/0.01 0.00/0.01 We now transform the resulting AFS into an AFSM by replacing all free variables by meta-variables (with arity 0). This leads to the following AFSM: 0.00/0.01 0.00/0.01 Alphabet: 0.00/0.01 0.00/0.01 a : [] --> N 0.00/0.01 f : [N] --> N 0.00/0.01 ~AP1 : [N -> N * N] --> N 0.00/0.01 0.00/0.01 Rules: 0.00/0.01 0.00/0.01 ~AP1(F, a) => f(a) 0.00/0.01 ~AP1(F, X) => F X 0.00/0.01 0.00/0.01 We use rule removal, following [Kop12, Theorem 2.23]. 0.00/0.01 0.00/0.01 This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): 0.00/0.01 0.00/0.01 ~AP1(F, a) >? f(a) 0.00/0.01 ~AP1(F, X) >? F X 0.00/0.01 0.00/0.01 We orient these requirements with a polynomial interpretation in the natural numbers. 0.00/0.01 0.00/0.01 The following interpretation satisfies the requirements: 0.00/0.01 0.00/0.01 a = 0 0.00/0.01 f = \y0.y0 0.00/0.01 ~AP1 = \G0y1.3 + 3y1 + G0(y1) 0.00/0.01 0.00/0.01 Using this interpretation, the requirements translate to: 0.00/0.01 0.00/0.01 [[~AP1(_F0, a)]] = 3 + F0(0) > 0 = [[f(a)]] 0.00/0.01 [[~AP1(_F0, _x1)]] = 3 + 3x1 + F0(x1) > x1 + F0(x1) = [[_F0 _x1]] 0.00/0.01 0.00/0.01 We can thus remove the following rules: 0.00/0.01 0.00/0.01 ~AP1(F, a) => f(a) 0.00/0.01 ~AP1(F, X) => F X 0.00/0.01 0.00/0.01 All rules were succesfully removed. Thus, termination of the original system has been reduced to termination of the beta-rule, which is well-known to hold. 0.00/0.01 0.00/0.01 0.00/0.01 +++ Citations +++ 0.00/0.01 0.00/0.01 [Kop11] C. Kop. Simplifying Algebraic Functional Systems. In Proceedings of CAI 2011, volume 6742 of LNCS. 201--215, Springer, 2011. 0.00/0.01 [Kop12] C. Kop. Higher Order Termination. PhD Thesis, 2012. 0.00/0.01 EOF