YES Problem: active(__(__(X,Y),Z)) -> mark(__(X,__(Y,Z))) active(__(X,nil())) -> mark(X) active(__(nil(),X)) -> mark(X) active(and(tt(),X)) -> mark(X) active(isList(V)) -> mark(isNeList(V)) active(isList(nil())) -> mark(tt()) active(isList(__(V1,V2))) -> mark(and(isList(V1),isList(V2))) active(isNeList(V)) -> mark(isQid(V)) active(isNeList(__(V1,V2))) -> mark(and(isList(V1),isNeList(V2))) active(isNeList(__(V1,V2))) -> mark(and(isNeList(V1),isList(V2))) active(isNePal(V)) -> mark(isQid(V)) active(isNePal(__(I,__(P,I)))) -> mark(and(isQid(I),isPal(P))) active(isPal(V)) -> mark(isNePal(V)) active(isPal(nil())) -> mark(tt()) active(isQid(a())) -> mark(tt()) active(isQid(e())) -> mark(tt()) active(isQid(i())) -> mark(tt()) active(isQid(o())) -> mark(tt()) active(isQid(u())) -> mark(tt()) mark(__(X1,X2)) -> active(__(mark(X1),mark(X2))) mark(nil()) -> active(nil()) mark(and(X1,X2)) -> active(and(mark(X1),X2)) mark(tt()) -> active(tt()) mark(isList(X)) -> active(isList(X)) mark(isNeList(X)) -> active(isNeList(X)) mark(isQid(X)) -> active(isQid(X)) mark(isNePal(X)) -> active(isNePal(X)) mark(isPal(X)) -> active(isPal(X)) mark(a()) -> active(a()) mark(e()) -> active(e()) mark(i()) -> active(i()) mark(o()) -> active(o()) mark(u()) -> active(u()) __(mark(X1),X2) -> __(X1,X2) __(X1,mark(X2)) -> __(X1,X2) __(active(X1),X2) -> __(X1,X2) __(X1,active(X2)) -> __(X1,X2) and(mark(X1),X2) -> and(X1,X2) and(X1,mark(X2)) -> and(X1,X2) and(active(X1),X2) -> and(X1,X2) and(X1,active(X2)) -> and(X1,X2) isList(mark(X)) -> isList(X) isList(active(X)) -> isList(X) isNeList(mark(X)) -> isNeList(X) isNeList(active(X)) -> isNeList(X) isQid(mark(X)) -> isQid(X) isQid(active(X)) -> isQid(X) isNePal(mark(X)) -> isNePal(X) isNePal(active(X)) -> isNePal(X) isPal(mark(X)) -> isPal(X) isPal(active(X)) -> isPal(X) Proof: Matrix Interpretation Processor: dim=1 interpretation: [u] = 0, [o] = 0, [i] = 4, [e] = 2, [a] = 4, [isPal](x0) = 3x0 + 3, [isNePal](x0) = 3x0 + 1, [isQid](x0) = 2x0, [isNeList](x0) = 2x0 + 2, [isList](x0) = 2x0 + 5, [and](x0, x1) = x0 + x1 + 5, [tt] = 0, [nil] = 3, [mark](x0) = x0, [active](x0) = x0, [__](x0, x1) = 2x0 + x1 + 5 orientation: active(__(__(X,Y),Z)) = 4X + 2Y + Z + 15 >= 2X + 2Y + Z + 10 = mark(__(X,__(Y,Z))) active(__(X,nil())) = 2X + 8 >= X = mark(X) active(__(nil(),X)) = X + 11 >= X = mark(X) active(and(tt(),X)) = X + 5 >= X = mark(X) active(isList(V)) = 2V + 5 >= 2V + 2 = mark(isNeList(V)) active(isList(nil())) = 11 >= 0 = mark(tt()) active(isList(__(V1,V2))) = 4V1 + 2V2 + 15 >= 2V1 + 2V2 + 15 = mark(and(isList(V1),isList(V2))) active(isNeList(V)) = 2V + 2 >= 2V = mark(isQid(V)) active(isNeList(__(V1,V2))) = 4V1 + 2V2 + 12 >= 2V1 + 2V2 + 12 = mark(and(isList(V1),isNeList(V2))) active(isNeList(__(V1,V2))) = 4V1 + 2V2 + 12 >= 2V1 + 2V2 + 12 = mark(and(isNeList(V1),isList(V2))) active(isNePal(V)) = 3V + 1 >= 2V = mark(isQid(V)) active(isNePal(__(I,__(P,I)))) = 9I + 6P + 31 >= 2I + 3P + 8 = mark(and(isQid(I),isPal(P))) active(isPal(V)) = 3V + 3 >= 3V + 1 = mark(isNePal(V)) active(isPal(nil())) = 12 >= 0 = mark(tt()) active(isQid(a())) = 8 >= 0 = mark(tt()) active(isQid(e())) = 4 >= 0 = mark(tt()) active(isQid(i())) = 8 >= 0 = mark(tt()) active(isQid(o())) = 0 >= 0 = mark(tt()) active(isQid(u())) = 0 >= 0 = mark(tt()) mark(__(X1,X2)) = 2X1 + X2 + 5 >= 2X1 + X2 + 5 = active(__(mark(X1),mark(X2))) mark(nil()) = 3 >= 3 = active(nil()) mark(and(X1,X2)) = X1 + X2 + 5 >= X1 + X2 + 5 = active(and(mark(X1),X2)) mark(tt()) = 0 >= 0 = active(tt()) mark(isList(X)) = 2X + 5 >= 2X + 5 = active(isList(X)) mark(isNeList(X)) = 2X + 2 >= 2X + 2 = active(isNeList(X)) mark(isQid(X)) = 2X >= 2X = active(isQid(X)) mark(isNePal(X)) = 3X + 1 >= 3X + 1 = active(isNePal(X)) mark(isPal(X)) = 3X + 3 >= 3X + 3 = active(isPal(X)) mark(a()) = 4 >= 4 = active(a()) mark(e()) = 2 >= 2 = active(e()) mark(i()) = 4 >= 4 = active(i()) mark(o()) = 0 >= 0 = active(o()) mark(u()) = 0 >= 0 = active(u()) __(mark(X1),X2) = 2X1 + X2 + 5 >= 2X1 + X2 + 5 = __(X1,X2) __(X1,mark(X2)) = 2X1 + X2 + 5 >= 2X1 + X2 + 5 = __(X1,X2) __(active(X1),X2) = 2X1 + X2 + 5 >= 2X1 + X2 + 5 = __(X1,X2) __(X1,active(X2)) = 2X1 + X2 + 5 >= 2X1 + X2 + 5 = __(X1,X2) and(mark(X1),X2) = X1 + X2 + 5 >= X1 + X2 + 5 = and(X1,X2) and(X1,mark(X2)) = X1 + X2 + 5 >= X1 + X2 + 5 = and(X1,X2) and(active(X1),X2) = X1 + X2 + 5 >= X1 + X2 + 5 = and(X1,X2) and(X1,active(X2)) = X1 + X2 + 5 >= X1 + X2 + 5 = and(X1,X2) isList(mark(X)) = 2X + 5 >= 2X + 5 = isList(X) isList(active(X)) = 2X + 5 >= 2X + 5 = isList(X) isNeList(mark(X)) = 2X + 2 >= 2X + 2 = isNeList(X) isNeList(active(X)) = 2X + 2 >= 2X + 2 = isNeList(X) isQid(mark(X)) = 2X >= 2X = isQid(X) isQid(active(X)) = 2X >= 2X = isQid(X) isNePal(mark(X)) = 3X + 1 >= 3X + 1 = isNePal(X) isNePal(active(X)) = 3X + 1 >= 3X + 1 = isNePal(X) isPal(mark(X)) = 3X + 3 >= 3X + 3 = isPal(X) isPal(active(X)) = 3X + 3 >= 3X + 3 = isPal(X) problem: active(isList(__(V1,V2))) -> mark(and(isList(V1),isList(V2))) active(isNeList(__(V1,V2))) -> mark(and(isList(V1),isNeList(V2))) active(isNeList(__(V1,V2))) -> mark(and(isNeList(V1),isList(V2))) active(isQid(o())) -> mark(tt()) active(isQid(u())) -> mark(tt()) mark(__(X1,X2)) -> active(__(mark(X1),mark(X2))) mark(nil()) -> active(nil()) mark(and(X1,X2)) -> active(and(mark(X1),X2)) mark(tt()) -> active(tt()) mark(isList(X)) -> active(isList(X)) mark(isNeList(X)) -> active(isNeList(X)) mark(isQid(X)) -> active(isQid(X)) mark(isNePal(X)) -> active(isNePal(X)) mark(isPal(X)) -> active(isPal(X)) mark(a()) -> active(a()) mark(e()) -> active(e()) mark(i()) -> active(i()) mark(o()) -> active(o()) mark(u()) -> active(u()) __(mark(X1),X2) -> __(X1,X2) __(X1,mark(X2)) -> __(X1,X2) __(active(X1),X2) -> __(X1,X2) __(X1,active(X2)) -> __(X1,X2) and(mark(X1),X2) -> and(X1,X2) and(X1,mark(X2)) -> and(X1,X2) and(active(X1),X2) -> and(X1,X2) and(X1,active(X2)) -> and(X1,X2) isList(mark(X)) -> isList(X) isList(active(X)) -> isList(X) isNeList(mark(X)) -> isNeList(X) isNeList(active(X)) -> isNeList(X) isQid(mark(X)) -> isQid(X) isQid(active(X)) -> isQid(X) isNePal(mark(X)) -> isNePal(X) isNePal(active(X)) -> isNePal(X) isPal(mark(X)) -> isPal(X) isPal(active(X)) -> isPal(X) LPO Processor: precedence: isNeList > isList > o ~ isQid > mark > u > i ~ e ~ a ~ isPal ~ isNePal ~ and ~ tt ~ nil ~ active ~ __ problem: Qed