/export/starexec/sandbox/solver/bin/starexec_run_FirstOrder /export/starexec/sandbox/benchmark/theBenchmark.xml /export/starexec/sandbox/output/output_files -------------------------------------------------------------------------------- YES We consider the system theBenchmark. We are asked to determine termination of the following first-order TRS. app : [o * o] --> o apply : [] --> o app(app(apply, X), Y) => app(X, Y) We use rule removal, following [Kop12, Theorem 2.23]. This gives the following requirements (possibly using Theorems 2.25 and 2.26 in [Kop12]): app(app(apply, X), Y) >? app(X, Y) We orient these requirements with a polynomial interpretation in the natural numbers. The following interpretation satisfies the requirements: app = \y0y1.3 + y0 + 3y1 apply = 3 Using this interpretation, the requirements translate to: [[app(app(apply, _x0), _x1)]] = 9 + 3x0 + 3x1 > 3 + x0 + 3x1 = [[app(_x0, _x1)]] We can thus remove the following rules: app(app(apply, X), Y) => app(X, Y) 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. +++ Citations +++ [Kop12] C. Kop. Higher Order Termination. PhD Thesis, 2012.