NO Problem: a__f(b(),X,c()) -> a__f(X,a__c(),X) a__c() -> b() mark(f(X1,X2,X3)) -> a__f(X1,mark(X2),X3) mark(c()) -> a__c() mark(b()) -> b() a__f(X1,X2,X3) -> f(X1,X2,X3) a__c() -> c() Proof: Matrix Interpretation Processor: dim=1 interpretation: [f](x0, x1, x2) = x0 + 6x1 + x2, [c] = 2, [a__c] = 2, [mark](x0) = 5x0, [b] = 2, [a__f](x0, x1, x2) = 5x0 + 6x1 + x2 orientation: a__f(b(),X,c()) = 6X + 12 >= 6X + 12 = a__f(X,a__c(),X) a__c() = 2 >= 2 = b() mark(f(X1,X2,X3)) = 5X1 + 30X2 + 5X3 >= 5X1 + 30X2 + X3 = a__f(X1,mark(X2),X3) mark(c()) = 10 >= 2 = a__c() mark(b()) = 10 >= 2 = b() a__f(X1,X2,X3) = 5X1 + 6X2 + X3 >= X1 + 6X2 + X3 = f(X1,X2,X3) a__c() = 2 >= 2 = c() problem: a__f(b(),X,c()) -> a__f(X,a__c(),X) a__c() -> b() mark(f(X1,X2,X3)) -> a__f(X1,mark(X2),X3) a__f(X1,X2,X3) -> f(X1,X2,X3) a__c() -> c() Matrix Interpretation Processor: dim=1 interpretation: [f](x0, x1, x2) = x0 + 2x1 + x2 + 4, [c] = 5, [a__c] = 5, [mark](x0) = 4x0 + 1, [b] = 5, [a__f](x0, x1, x2) = x0 + 2x1 + x2 + 7 orientation: a__f(b(),X,c()) = 2X + 17 >= 2X + 17 = a__f(X,a__c(),X) a__c() = 5 >= 5 = b() mark(f(X1,X2,X3)) = 4X1 + 8X2 + 4X3 + 17 >= X1 + 8X2 + X3 + 9 = a__f(X1,mark(X2),X3) a__f(X1,X2,X3) = X1 + 2X2 + X3 + 7 >= X1 + 2X2 + X3 + 4 = f(X1,X2,X3) a__c() = 5 >= 5 = c() problem: a__f(b(),X,c()) -> a__f(X,a__c(),X) a__c() -> b() a__c() -> c() Unfolding Processor: loop length: 3 terms: a__f(a__c(),a__c(),a__c()) a__f(a__c(),a__c(),c()) a__f(b(),a__c(),c()) context: [] substitution: Qed