YES(?,O(n^2)) Problem: half(0()) -> 0() half(s(s(x))) -> s(half(x)) log(s(0())) -> 0() log(s(s(x))) -> s(log(s(half(x)))) Proof: Complexity Transformation Processor: strict: half(0()) -> 0() half(s(s(x))) -> s(half(x)) log(s(0())) -> 0() log(s(s(x))) -> s(log(s(half(x)))) weak: Matrix Interpretation Processor: dimension: 1 max_matrix: 1 interpretation: [log](x0) = x0 + 1, [s](x0) = x0, [half](x0) = x0, [0] = 1 orientation: half(0()) = 1 >= 1 = 0() half(s(s(x))) = x >= x = s(half(x)) log(s(0())) = 2 >= 1 = 0() log(s(s(x))) = x + 1 >= x + 1 = s(log(s(half(x)))) problem: strict: half(0()) -> 0() half(s(s(x))) -> s(half(x)) log(s(s(x))) -> s(log(s(half(x)))) weak: log(s(0())) -> 0() Matrix Interpretation Processor: dimension: 1 max_matrix: 1 interpretation: [log](x0) = x0, [s](x0) = x0 + 1, [half](x0) = x0 + 1, [0] = 1 orientation: half(0()) = 2 >= 1 = 0() half(s(s(x))) = x + 3 >= x + 2 = s(half(x)) log(s(s(x))) = x + 2 >= x + 3 = s(log(s(half(x)))) log(s(0())) = 2 >= 1 = 0() problem: strict: log(s(s(x))) -> s(log(s(half(x)))) weak: half(0()) -> 0() half(s(s(x))) -> s(half(x)) log(s(0())) -> 0() Matrix Interpretation Processor: dimension: 2 max_matrix: [1 1] [0 1] interpretation: [1 1] [1] [log](x0) = [0 1]x0 + [0], [0] [s](x0) = x0 + [1], [half](x0) = x0, [0] [0] = [0] orientation: [1 1] [3] [1 1] [2] log(s(s(x))) = [0 1]x + [2] >= [0 1]x + [2] = s(log(s(half(x)))) [0] [0] half(0()) = [0] >= [0] = 0() [0] [0] half(s(s(x))) = x + [2] >= x + [1] = s(half(x)) [2] [0] log(s(0())) = [1] >= [0] = 0() problem: strict: weak: log(s(s(x))) -> s(log(s(half(x)))) half(0()) -> 0() half(s(s(x))) -> s(half(x)) log(s(0())) -> 0() Qed