YES Problem: le(0(),y) -> true() le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) gcd(0(),y) -> y gcd(s(x),0()) -> s(x) gcd(s(x),s(y)) -> if_gcd(le(y,x),s(x),s(y)) if_gcd(true(),s(x),s(y)) -> gcd(minus(x,y),s(y)) if_gcd(false(),s(x),s(y)) -> gcd(minus(y,x),s(x)) Proof: DP Processor: DPs: le#(s(x),s(y)) -> le#(x,y) minus#(s(x),s(y)) -> minus#(x,y) gcd#(s(x),s(y)) -> le#(y,x) gcd#(s(x),s(y)) -> if_gcd#(le(y,x),s(x),s(y)) if_gcd#(true(),s(x),s(y)) -> minus#(x,y) if_gcd#(true(),s(x),s(y)) -> gcd#(minus(x,y),s(y)) if_gcd#(false(),s(x),s(y)) -> minus#(y,x) if_gcd#(false(),s(x),s(y)) -> gcd#(minus(y,x),s(x)) TRS: le(0(),y) -> true() le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) gcd(0(),y) -> y gcd(s(x),0()) -> s(x) gcd(s(x),s(y)) -> if_gcd(le(y,x),s(x),s(y)) if_gcd(true(),s(x),s(y)) -> gcd(minus(x,y),s(y)) if_gcd(false(),s(x),s(y)) -> gcd(minus(y,x),s(x)) Usable Rule Processor: DPs: le#(s(x),s(y)) -> le#(x,y) minus#(s(x),s(y)) -> minus#(x,y) gcd#(s(x),s(y)) -> le#(y,x) gcd#(s(x),s(y)) -> if_gcd#(le(y,x),s(x),s(y)) if_gcd#(true(),s(x),s(y)) -> minus#(x,y) if_gcd#(true(),s(x),s(y)) -> gcd#(minus(x,y),s(y)) if_gcd#(false(),s(x),s(y)) -> minus#(y,x) if_gcd#(false(),s(x),s(y)) -> gcd#(minus(y,x),s(x)) TRS: le(0(),y) -> true() le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) Matrix Interpretation Processor: dim=1 usable rules: le(0(),y) -> true() le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) interpretation: [if_gcd#](x0, x1, x2) = x0 + x1 + x2 + 1, [gcd#](x0, x1) = x0 + x1 + 2, [minus#](x0, x1) = x1 + 1/2, [le#](x0, x1) = x0 + 3/2, [minus](x0, x1) = x0, [false] = 1/2, [s](x0) = 3/2x0 + 2, [true] = 0, [le](x0, x1) = 1/2, [0] = 0 orientation: le#(s(x),s(y)) = 3/2x + 7/2 >= x + 3/2 = le#(x,y) minus#(s(x),s(y)) = 3/2y + 5/2 >= y + 1/2 = minus#(x,y) gcd#(s(x),s(y)) = 3/2x + 3/2y + 6 >= y + 3/2 = le#(y,x) gcd#(s(x),s(y)) = 3/2x + 3/2y + 6 >= 3/2x + 3/2y + 11/2 = if_gcd#(le(y,x),s(x),s(y)) if_gcd#(true(),s(x),s(y)) = 3/2x + 3/2y + 5 >= y + 1/2 = minus#(x,y) if_gcd#(true(),s(x),s(y)) = 3/2x + 3/2y + 5 >= x + 3/2y + 4 = gcd#(minus(x,y),s(y)) if_gcd#(false(),s(x),s(y)) = 3/2x + 3/2y + 11/2 >= x + 1/2 = minus#(y,x) if_gcd#(false(),s(x),s(y)) = 3/2x + 3/2y + 11/2 >= 3/2x + y + 4 = gcd#(minus(y,x),s(x)) le(0(),y) = 1/2 >= 0 = true() le(s(x),0()) = 1/2 >= 1/2 = false() le(s(x),s(y)) = 1/2 >= 1/2 = le(x,y) minus(x,0()) = x >= x = x minus(s(x),s(y)) = 3/2x + 2 >= x = minus(x,y) problem: DPs: TRS: le(0(),y) -> true() le(s(x),0()) -> false() le(s(x),s(y)) -> le(x,y) minus(x,0()) -> x minus(s(x),s(y)) -> minus(x,y) Qed