YES Problem: a__eq(0(),0()) -> true() a__eq(s(X),s(Y)) -> a__eq(X,Y) a__eq(X,Y) -> false() a__inf(X) -> cons(X,inf(s(X))) a__take(0(),X) -> nil() a__take(s(X),cons(Y,L)) -> cons(Y,take(X,L)) a__length(nil()) -> 0() a__length(cons(X,L)) -> s(length(L)) mark(eq(X1,X2)) -> a__eq(X1,X2) mark(inf(X)) -> a__inf(mark(X)) mark(take(X1,X2)) -> a__take(mark(X1),mark(X2)) mark(length(X)) -> a__length(mark(X)) mark(0()) -> 0() mark(true()) -> true() mark(s(X)) -> s(X) mark(false()) -> false() mark(cons(X1,X2)) -> cons(X1,X2) mark(nil()) -> nil() a__eq(X1,X2) -> eq(X1,X2) a__inf(X) -> inf(X) a__take(X1,X2) -> take(X1,X2) a__length(X) -> length(X) Proof: DP Processor: DPs: a__eq#(s(X),s(Y)) -> a__eq#(X,Y) mark#(eq(X1,X2)) -> a__eq#(X1,X2) mark#(inf(X)) -> mark#(X) mark#(inf(X)) -> a__inf#(mark(X)) mark#(take(X1,X2)) -> mark#(X2) mark#(take(X1,X2)) -> mark#(X1) mark#(take(X1,X2)) -> a__take#(mark(X1),mark(X2)) mark#(length(X)) -> mark#(X) mark#(length(X)) -> a__length#(mark(X)) TRS: a__eq(0(),0()) -> true() a__eq(s(X),s(Y)) -> a__eq(X,Y) a__eq(X,Y) -> false() a__inf(X) -> cons(X,inf(s(X))) a__take(0(),X) -> nil() a__take(s(X),cons(Y,L)) -> cons(Y,take(X,L)) a__length(nil()) -> 0() a__length(cons(X,L)) -> s(length(L)) mark(eq(X1,X2)) -> a__eq(X1,X2) mark(inf(X)) -> a__inf(mark(X)) mark(take(X1,X2)) -> a__take(mark(X1),mark(X2)) mark(length(X)) -> a__length(mark(X)) mark(0()) -> 0() mark(true()) -> true() mark(s(X)) -> s(X) mark(false()) -> false() mark(cons(X1,X2)) -> cons(X1,X2) mark(nil()) -> nil() a__eq(X1,X2) -> eq(X1,X2) a__inf(X) -> inf(X) a__take(X1,X2) -> take(X1,X2) a__length(X) -> length(X) Arctic Interpretation Processor: dimension: 1 usable rules: interpretation: [mark#](x0) = x0, [a__length#](x0) = 0, [a__take#](x0, x1) = 0, [a__inf#](x0) = 0, [a__eq#](x0, x1) = x0 + 1x1, [mark](x0) = x0 + 0, [eq](x0, x1) = 1x0 + 4x1, [length](x0) = 4x0 + 1, [a__length](x0) = x0 + 6, [take](x0, x1) = 7x0 + 6x1 + 3, [nil] = 6, [a__take](x0, x1) = x0 + x1 + 8, [cons](x0, x1) = x0 + 1, [inf](x0) = 4x0 + 5, [a__inf](x0) = 0, [false] = 7, [s](x0) = 1x0 + 0, [true] = 2, [a__eq](x0, x1) = 3x0 + x1 + 6, [0] = 1 orientation: a__eq#(s(X),s(Y)) = 1X + 2Y + 1 >= X + 1Y = a__eq#(X,Y) mark#(eq(X1,X2)) = 1X1 + 4X2 >= X1 + 1X2 = a__eq#(X1,X2) mark#(inf(X)) = 4X + 5 >= X = mark#(X) mark#(inf(X)) = 4X + 5 >= 0 = a__inf#(mark(X)) mark#(take(X1,X2)) = 7X1 + 6X2 + 3 >= X2 = mark#(X2) mark#(take(X1,X2)) = 7X1 + 6X2 + 3 >= X1 = mark#(X1) mark#(take(X1,X2)) = 7X1 + 6X2 + 3 >= 0 = a__take#(mark(X1),mark(X2)) mark#(length(X)) = 4X + 1 >= X = mark#(X) mark#(length(X)) = 4X + 1 >= 0 = a__length#(mark(X)) a__eq(0(),0()) = 6 >= 2 = true() a__eq(s(X),s(Y)) = 4X + 1Y + 6 >= 3X + Y + 6 = a__eq(X,Y) a__eq(X,Y) = 3X + Y + 6 >= 7 = false() a__inf(X) = 0 >= X + 1 = cons(X,inf(s(X))) a__take(0(),X) = X + 8 >= 6 = nil() a__take(s(X),cons(Y,L)) = 1X + Y + 8 >= Y + 1 = cons(Y,take(X,L)) a__length(nil()) = 6 >= 1 = 0() a__length(cons(X,L)) = X + 6 >= 5L + 2 = s(length(L)) mark(eq(X1,X2)) = 1X1 + 4X2 + 0 >= 3X1 + X2 + 6 = a__eq(X1,X2) mark(inf(X)) = 4X + 5 >= 0 = a__inf(mark(X)) mark(take(X1,X2)) = 7X1 + 6X2 + 3 >= X1 + X2 + 8 = a__take(mark(X1),mark(X2)) mark(length(X)) = 4X + 1 >= X + 6 = a__length(mark(X)) mark(0()) = 1 >= 1 = 0() mark(true()) = 2 >= 2 = true() mark(s(X)) = 1X + 0 >= 1X + 0 = s(X) mark(false()) = 7 >= 7 = false() mark(cons(X1,X2)) = X1 + 1 >= X1 + 1 = cons(X1,X2) mark(nil()) = 6 >= 6 = nil() a__eq(X1,X2) = 3X1 + X2 + 6 >= 1X1 + 4X2 = eq(X1,X2) a__inf(X) = 0 >= 4X + 5 = inf(X) a__take(X1,X2) = X1 + X2 + 8 >= 7X1 + 6X2 + 3 = take(X1,X2) a__length(X) = X + 6 >= 4X + 1 = length(X) problem: DPs: TRS: a__eq(0(),0()) -> true() a__eq(s(X),s(Y)) -> a__eq(X,Y) a__eq(X,Y) -> false() a__inf(X) -> cons(X,inf(s(X))) a__take(0(),X) -> nil() a__take(s(X),cons(Y,L)) -> cons(Y,take(X,L)) a__length(nil()) -> 0() a__length(cons(X,L)) -> s(length(L)) mark(eq(X1,X2)) -> a__eq(X1,X2) mark(inf(X)) -> a__inf(mark(X)) mark(take(X1,X2)) -> a__take(mark(X1),mark(X2)) mark(length(X)) -> a__length(mark(X)) mark(0()) -> 0() mark(true()) -> true() mark(s(X)) -> s(X) mark(false()) -> false() mark(cons(X1,X2)) -> cons(X1,X2) mark(nil()) -> nil() a__eq(X1,X2) -> eq(X1,X2) a__inf(X) -> inf(X) a__take(X1,X2) -> take(X1,X2) a__length(X) -> length(X) Qed