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 and : [c * c] --> c 0.00/0.01 arrow : [t * t] --> t 0.00/0.01 lessthan : [t * t] --> c 0.00/0.01 0.00/0.01 Rules: 0.00/0.01 0.00/0.01 lessthan(arrow(x, y), arrow(z, u)) => and(lessthan(z, x), lessthan(y, u)) 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 lessthan(arrow(X, Y), arrow(Z, U)) >? and(lessthan(Z, X), lessthan(Y, U)) 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 and = \y0y1.y0 + y1 0.00/0.01 arrow = \y0y1.3 + 3y0 + 3y1 0.00/0.01 lessthan = \y0y1.2y0 + 3y1 0.00/0.01 0.00/0.01 Using this interpretation, the requirements translate to: 0.00/0.01 0.00/0.01 [[lessthan(arrow(_x0, _x1), arrow(_x2, _x3))]] = 15 + 6x0 + 6x1 + 9x2 + 9x3 > 2x1 + 2x2 + 3x0 + 3x3 = [[and(lessthan(_x2, _x0), lessthan(_x1, _x3))]] 0.00/0.01 0.00/0.01 We can thus remove the following rules: 0.00/0.01 0.00/0.01 lessthan(arrow(X, Y), arrow(Z, U)) => and(lessthan(Z, X), lessthan(Y, U)) 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