YES O(n^2) TRS: { a__h(X) -> h(X), a__h(d()) -> a__g(c()), a__g(X) -> a__h(X), a__g(X) -> g(X), a__c() -> d(), a__c() -> c(), mark(d()) -> d(), mark(c()) -> a__c(), mark(g(X)) -> a__g(X), mark(h(X)) -> a__h(X) } DUP: We consider a non-duplicating system. Trs: { a__h(X) -> h(X), a__h(d()) -> a__g(c()), a__g(X) -> a__h(X), a__g(X) -> g(X), a__c() -> d(), a__c() -> c(), mark(d()) -> d(), mark(c()) -> a__c(), mark(g(X)) -> a__g(X), mark(h(X)) -> a__h(X) } Matrix Interpretation: Interpretation class: triangular [X1] [1 2][X1] [0] [h]([X0]) = [0 0][X0] + [0] [X1] [1 2][X1] [1] [g]([X0]) = [0 0][X0] + [0] [X1] [1 0][X1] [2] [mark]([X0]) = [0 0][X0] + [2] [0] [c] = [0] [1] [a__c] = [2] [0] [d] = [2] [X1] [1 2][X1] [2] [a__g]([X0]) = [0 0][X0] + [0] [X1] [1 2][X1] [1] [a__h]([X0]) = [0 0][X0] + [0] Qed