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 minus : [N * N] --> N 0.00/0.01 s : [N] --> N 0.00/0.01 z : [] --> N 0.00/0.01 0.00/0.01 Rules: 0.00/0.01 0.00/0.01 minus(z, x) => z 0.00/0.01 minus(x, z) => x 0.00/0.01 minus(s(x), s(y)) => minus(x, y) 0.00/0.01 minus(x, x) => z 0.00/0.01 0.00/0.01 This AFS is converted to an AFSM simply by replacing all free variables by meta-variables (with arity 0). 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 minus(z, X) >? z 0.00/0.01 minus(X, z) >? X 0.00/0.01 minus(s(X), s(Y)) >? minus(X, Y) 0.00/0.01 minus(X, X) >? z 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 minus = \y0y1.3 + y1 + 3y0 0.00/0.01 s = \y0.3 + 3y0 0.00/0.01 z = 0 0.00/0.01 0.00/0.01 Using this interpretation, the requirements translate to: 0.00/0.01 0.00/0.01 [[minus(z, _x0)]] = 3 + x0 > 0 = [[z]] 0.00/0.01 [[minus(_x0, z)]] = 3 + 3x0 > x0 = [[_x0]] 0.00/0.01 [[minus(s(_x0), s(_x1))]] = 15 + 3x1 + 9x0 > 3 + x1 + 3x0 = [[minus(_x0, _x1)]] 0.00/0.01 [[minus(_x0, _x0)]] = 3 + 4x0 > 0 = [[z]] 0.00/0.01 0.00/0.01 We can thus remove the following rules: 0.00/0.01 0.00/0.01 minus(z, X) => z 0.00/0.01 minus(X, z) => X 0.00/0.01 minus(s(X), s(Y)) => minus(X, Y) 0.00/0.01 minus(X, X) => z 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 [Kop12] C. Kop. Higher Order Termination. PhD Thesis, 2012. 0.00/0.01 EOF