YES Problem: minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) f(0()) -> s(0()) f(s(x)) -> minus(s(x),g(f(x))) g(0()) -> 0() g(s(x)) -> minus(s(x),f(g(x))) Proof: DP Processor: DPs: minus#(s(x),s(y)) -> minus#(x,y) f#(s(x)) -> f#(x) f#(s(x)) -> g#(f(x)) f#(s(x)) -> minus#(s(x),g(f(x))) g#(s(x)) -> g#(x) g#(s(x)) -> f#(g(x)) g#(s(x)) -> minus#(s(x),f(g(x))) TRS: minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) f(0()) -> s(0()) f(s(x)) -> minus(s(x),g(f(x))) g(0()) -> 0() g(s(x)) -> minus(s(x),f(g(x))) TDG Processor: DPs: minus#(s(x),s(y)) -> minus#(x,y) f#(s(x)) -> f#(x) f#(s(x)) -> g#(f(x)) f#(s(x)) -> minus#(s(x),g(f(x))) g#(s(x)) -> g#(x) g#(s(x)) -> f#(g(x)) g#(s(x)) -> minus#(s(x),f(g(x))) TRS: minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) f(0()) -> s(0()) f(s(x)) -> minus(s(x),g(f(x))) g(0()) -> 0() g(s(x)) -> minus(s(x),f(g(x))) graph: g#(s(x)) -> g#(x) -> g#(s(x)) -> minus#(s(x),f(g(x))) g#(s(x)) -> g#(x) -> g#(s(x)) -> f#(g(x)) g#(s(x)) -> g#(x) -> g#(s(x)) -> g#(x) g#(s(x)) -> f#(g(x)) -> f#(s(x)) -> minus#(s(x),g(f(x))) g#(s(x)) -> f#(g(x)) -> f#(s(x)) -> g#(f(x)) g#(s(x)) -> f#(g(x)) -> f#(s(x)) -> f#(x) g#(s(x)) -> minus#(s(x),f(g(x))) -> minus#(s(x),s(y)) -> minus#(x,y) f#(s(x)) -> g#(f(x)) -> g#(s(x)) -> minus#(s(x),f(g(x))) f#(s(x)) -> g#(f(x)) -> g#(s(x)) -> f#(g(x)) f#(s(x)) -> g#(f(x)) -> g#(s(x)) -> g#(x) f#(s(x)) -> f#(x) -> f#(s(x)) -> minus#(s(x),g(f(x))) f#(s(x)) -> f#(x) -> f#(s(x)) -> g#(f(x)) f#(s(x)) -> f#(x) -> f#(s(x)) -> f#(x) f#(s(x)) -> minus#(s(x),g(f(x))) -> minus#(s(x),s(y)) -> minus#(x,y) minus#(s(x),s(y)) -> minus#(x,y) -> minus#(s(x),s(y)) -> minus#(x,y) SCC Processor: #sccs: 2 #rules: 5 #arcs: 15/49 DPs: g#(s(x)) -> g#(x) g#(s(x)) -> f#(g(x)) f#(s(x)) -> f#(x) f#(s(x)) -> g#(f(x)) TRS: minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) f(0()) -> s(0()) f(s(x)) -> minus(s(x),g(f(x))) g(0()) -> 0() g(s(x)) -> minus(s(x),f(g(x))) KBO Processor: argument filtering: pi(0) = [] pi(minus) = 0 pi(s) = [0] pi(f) = [0] pi(g) = 0 pi(f#) = [0] pi(g#) = [0] weight function: w0 = 1 w(f#) = w(f) = w(s) = w(minus) = w(0) = 1 w(g#) = w(g) = 0 precedence: g# ~ f > f# ~ g ~ s ~ minus ~ 0 problem: DPs: TRS: minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) f(0()) -> s(0()) f(s(x)) -> minus(s(x),g(f(x))) g(0()) -> 0() g(s(x)) -> minus(s(x),f(g(x))) Qed DPs: minus#(s(x),s(y)) -> minus#(x,y) TRS: minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) f(0()) -> s(0()) f(s(x)) -> minus(s(x),g(f(x))) g(0()) -> 0() g(s(x)) -> minus(s(x),f(g(x))) Arctic Interpretation Processor: dimension: 1 interpretation: [minus#](x0, x1) = 3x0 + x1, [g](x0) = 2x0 + 3, [f](x0) = 4x0 + 1, [s](x0) = 1x0 + 0, [minus](x0, x1) = 1x0, [0] = 0 orientation: minus#(s(x),s(y)) = 4x + 1y + 3 >= 3x + y = minus#(x,y) minus(x,0()) = 1x >= x = x minus(s(x),s(y)) = 2x + 1 >= 1x = minus(x,y) f(0()) = 4 >= 1 = s(0()) f(s(x)) = 5x + 4 >= 2x + 1 = minus(s(x),g(f(x))) g(0()) = 3 >= 0 = 0() g(s(x)) = 3x + 3 >= 2x + 1 = minus(s(x),f(g(x))) problem: DPs: TRS: minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) f(0()) -> s(0()) f(s(x)) -> minus(s(x),g(f(x))) g(0()) -> 0() g(s(x)) -> minus(s(x),f(g(x))) Qed