YES Problem: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) times(X,s(Y)) -> plus(X,times(Y,X)) Proof: DP Processor: DPs: plus#(plus(X,Y),Z) -> plus#(Y,Z) plus#(plus(X,Y),Z) -> plus#(X,plus(Y,Z)) times#(X,s(Y)) -> times#(Y,X) times#(X,s(Y)) -> plus#(X,times(Y,X)) TRS: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) times(X,s(Y)) -> plus(X,times(Y,X)) Matrix Interpretation Processor: dim=1 interpretation: [times#](x0, x1) = 5x0 + 4x1, [plus#](x0, x1) = 4x0 + 2, [times](x0, x1) = 5x0 + x1 + 4, [s](x0) = 6x0 + 4, [plus](x0, x1) = 4x0 + x1 + 4 orientation: plus#(plus(X,Y),Z) = 16X + 4Y + 18 >= 4Y + 2 = plus#(Y,Z) plus#(plus(X,Y),Z) = 16X + 4Y + 18 >= 4X + 2 = plus#(X,plus(Y,Z)) times#(X,s(Y)) = 5X + 24Y + 16 >= 4X + 5Y = times#(Y,X) times#(X,s(Y)) = 5X + 24Y + 16 >= 4X + 2 = plus#(X,times(Y,X)) plus(plus(X,Y),Z) = 16X + 4Y + Z + 20 >= 4X + 4Y + Z + 8 = plus(X,plus(Y,Z)) times(X,s(Y)) = 5X + 6Y + 8 >= 5X + 5Y + 8 = plus(X,times(Y,X)) problem: DPs: TRS: plus(plus(X,Y),Z) -> plus(X,plus(Y,Z)) times(X,s(Y)) -> plus(X,times(Y,X)) Qed