YES Problem: le(0(),y) -> true() le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) minus(0(),y) -> 0() minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) if_minus(true(),s(x),y) -> 0() if_minus(false(),s(x),y) -> s(minus(x,y)) quot(0(),s(y)) -> 0() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) log(s(0())) -> 0() log(s(s(x))) -> s(log(s(quot(x,s(s(0())))))) Proof: DP Processor: DPs: le#(s(x),s(y)) -> le#(x,y) minus#(s(x),y) -> le#(s(x),y) minus#(s(x),y) -> if_minus#(le(s(x),y),s(x),y) if_minus#(false(),s(x),y) -> minus#(x,y) quot#(s(x),s(y)) -> minus#(x,y) quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) log#(s(s(x))) -> quot#(x,s(s(0()))) log#(s(s(x))) -> log#(s(quot(x,s(s(0()))))) TRS: le(0(),y) -> true() le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) minus(0(),y) -> 0() minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) if_minus(true(),s(x),y) -> 0() if_minus(false(),s(x),y) -> s(minus(x,y)) quot(0(),s(y)) -> 0() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) log(s(0())) -> 0() log(s(s(x))) -> s(log(s(quot(x,s(s(0())))))) Usable Rule Processor: DPs: le#(s(x),s(y)) -> le#(x,y) minus#(s(x),y) -> le#(s(x),y) minus#(s(x),y) -> if_minus#(le(s(x),y),s(x),y) if_minus#(false(),s(x),y) -> minus#(x,y) quot#(s(x),s(y)) -> minus#(x,y) quot#(s(x),s(y)) -> quot#(minus(x,y),s(y)) log#(s(s(x))) -> quot#(x,s(s(0()))) log#(s(s(x))) -> log#(s(quot(x,s(s(0()))))) TRS: le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) le(0(),y) -> true() minus(0(),y) -> 0() minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) if_minus(true(),s(x),y) -> 0() if_minus(false(),s(x),y) -> s(minus(x,y)) quot(0(),s(y)) -> 0() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) Matrix Interpretation Processor: dim=1 usable rules: minus(0(),y) -> 0() minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) if_minus(true(),s(x),y) -> 0() if_minus(false(),s(x),y) -> s(minus(x,y)) quot(0(),s(y)) -> 0() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) interpretation: [log#](x0) = 1/2x0 + 2, [quot#](x0, x1) = 2x0 + 1/2, [if_minus#](x0, x1, x2) = x1 + 1/2, [minus#](x0, x1) = 2x0 + 1, [le#](x0, x1) = 1/2x0, [quot](x0, x1) = 2x0 + 1/2, [if_minus](x0, x1, x2) = x1, [minus](x0, x1) = x0, [false] = 0, [s](x0) = 2x0 + 1, [true] = 0, [le](x0, x1) = 0, [0] = 1/2 orientation: le#(s(x),s(y)) = x + 1/2 >= 1/2x = le#(x,y) minus#(s(x),y) = 4x + 3 >= x + 1/2 = le#(s(x),y) minus#(s(x),y) = 4x + 3 >= 2x + 3/2 = if_minus#(le(s(x),y),s(x),y) if_minus#(false(),s(x),y) = 2x + 3/2 >= 2x + 1 = minus#(x,y) quot#(s(x),s(y)) = 4x + 5/2 >= 2x + 1 = minus#(x,y) quot#(s(x),s(y)) = 4x + 5/2 >= 2x + 1/2 = quot#(minus(x,y),s(y)) log#(s(s(x))) = 2x + 7/2 >= 2x + 1/2 = quot#(x,s(s(0()))) log#(s(s(x))) = 2x + 7/2 >= 2x + 3 = log#(s(quot(x,s(s(0()))))) le(s(x),0()) = 0 >= 0 = false() le(s(x),s(y)) = 0 >= 0 = le(x,y) le(0(),y) = 0 >= 0 = true() minus(0(),y) = 1/2 >= 1/2 = 0() minus(s(x),y) = 2x + 1 >= 2x + 1 = if_minus(le(s(x),y),s(x),y) if_minus(true(),s(x),y) = 2x + 1 >= 1/2 = 0() if_minus(false(),s(x),y) = 2x + 1 >= 2x + 1 = s(minus(x,y)) quot(0(),s(y)) = 3/2 >= 1/2 = 0() quot(s(x),s(y)) = 4x + 5/2 >= 4x + 2 = s(quot(minus(x,y),s(y))) problem: DPs: TRS: le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) le(0(),y) -> true() minus(0(),y) -> 0() minus(s(x),y) -> if_minus(le(s(x),y),s(x),y) if_minus(true(),s(x),y) -> 0() if_minus(false(),s(x),y) -> s(minus(x,y)) quot(0(),s(y)) -> 0() quot(s(x),s(y)) -> s(quot(minus(x,y),s(y))) Qed