YES Problem: -(x,0()) -> x -(s(x),s(y)) -> -(x,y) *(x,0()) -> 0() *(x,s(y)) -> +(*(x,y),x) if(true(),x,y) -> x if(false(),x,y) -> y odd(0()) -> false() odd(s(0())) -> true() odd(s(s(x))) -> odd(x) half(0()) -> 0() half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) if(true(),x,y) -> true() if(false(),x,y) -> false() pow(x,y) -> f(x,y,s(0())) f(x,0(),z) -> z f(x,s(y),z) -> if(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) Proof: DP Processor: DPs: -#(s(x),s(y)) -> -#(x,y) *#(x,s(y)) -> *#(x,y) odd#(s(s(x))) -> odd#(x) half#(s(s(x))) -> half#(x) pow#(x,y) -> f#(x,y,s(0())) f#(x,s(y),z) -> half#(s(y)) f#(x,s(y),z) -> *#(x,x) f#(x,s(y),z) -> f#(*(x,x),half(s(y)),z) f#(x,s(y),z) -> *#(x,z) f#(x,s(y),z) -> f#(x,y,*(x,z)) f#(x,s(y),z) -> odd#(s(y)) f#(x,s(y),z) -> if#(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) TRS: -(x,0()) -> x -(s(x),s(y)) -> -(x,y) *(x,0()) -> 0() *(x,s(y)) -> +(*(x,y),x) if(true(),x,y) -> x if(false(),x,y) -> y odd(0()) -> false() odd(s(0())) -> true() odd(s(s(x))) -> odd(x) half(0()) -> 0() half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) if(true(),x,y) -> true() if(false(),x,y) -> false() pow(x,y) -> f(x,y,s(0())) f(x,0(),z) -> z f(x,s(y),z) -> if(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) Usable Rule Processor: DPs: -#(s(x),s(y)) -> -#(x,y) *#(x,s(y)) -> *#(x,y) odd#(s(s(x))) -> odd#(x) half#(s(s(x))) -> half#(x) pow#(x,y) -> f#(x,y,s(0())) f#(x,s(y),z) -> half#(s(y)) f#(x,s(y),z) -> *#(x,x) f#(x,s(y),z) -> f#(*(x,x),half(s(y)),z) f#(x,s(y),z) -> *#(x,z) f#(x,s(y),z) -> f#(x,y,*(x,z)) f#(x,s(y),z) -> odd#(s(y)) f#(x,s(y),z) -> if#(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) TRS: half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) half(0()) -> 0() *(x,0()) -> 0() *(x,s(y)) -> +(*(x,y),x) f(x,0(),z) -> z f(x,s(y),z) -> if(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) if(true(),x,y) -> x if(false(),x,y) -> y if(true(),x,y) -> true() if(false(),x,y) -> false() odd(s(0())) -> true() odd(s(s(x))) -> odd(x) odd(0()) -> false() Matrix Interpretation Processor: dim=1 usable rules: half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) half(0()) -> 0() *(x,0()) -> 0() *(x,s(y)) -> +(*(x,y),x) interpretation: [f#](x0, x1, x2) = 2x0 + 3x1 + x2, [pow#](x0, x1) = 5/2x0 + 3x1 + 3/2, [half#](x0) = x0 + 1/2, [odd#](x0) = 5/2x0, [if#](x0, x1, x2) = 3/2, [*#](x0, x1) = 1/2x1 + 2, [-#](x0, x1) = 3x0 + 2x1 + 7/2, [f](x0, x1, x2) = 2x0 + x2 + 1, [half](x0) = 1/2x0, [odd](x0) = x0, [false] = 2, [if](x0, x1, x2) = 1/2x0 + x1 + 5/2x2 + 3/2, [true] = 3, [+](x0, x1) = 0, [*](x0, x1) = 1/2x1 + 1/2, [s](x0) = 2x0 + 1, [0] = 0 orientation: -#(s(x),s(y)) = 6x + 4y + 17/2 >= 3x + 2y + 7/2 = -#(x,y) *#(x,s(y)) = y + 5/2 >= 1/2y + 2 = *#(x,y) odd#(s(s(x))) = 10x + 15/2 >= 5/2x = odd#(x) half#(s(s(x))) = 4x + 7/2 >= x + 1/2 = half#(x) pow#(x,y) = 5/2x + 3y + 3/2 >= 2x + 3y + 1 = f#(x,y,s(0())) f#(x,s(y),z) = 2x + 6y + z + 3 >= 2y + 3/2 = half#(s(y)) f#(x,s(y),z) = 2x + 6y + z + 3 >= 1/2x + 2 = *#(x,x) f#(x,s(y),z) = 2x + 6y + z + 3 >= x + 3y + z + 5/2 = f#(*(x,x),half(s(y)),z) f#(x,s(y),z) = 2x + 6y + z + 3 >= 1/2z + 2 = *#(x,z) f#(x,s(y),z) = 2x + 6y + z + 3 >= 2x + 3y + 1/2z + 1/2 = f#(x,y,*(x,z)) f#(x,s(y),z) = 2x + 6y + z + 3 >= 5y + 5/2 = odd#(s(y)) f#(x,s(y),z) = 2x + 6y + z + 3 >= 3/2 = if#(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) half(s(0())) = 1/2 >= 0 = 0() half(s(s(x))) = 2x + 3/2 >= x + 1 = s(half(x)) half(0()) = 0 >= 0 = 0() *(x,0()) = 1/2 >= 0 = 0() *(x,s(y)) = y + 1 >= 0 = +(*(x,y),x) f(x,0(),z) = 2x + z + 1 >= z = z f(x,s(y),z) = 2x + z + 1 >= 9/2x + y + 3z + 17/2 = if(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) if(true(),x,y) = x + 5/2y + 3 >= x = x if(false(),x,y) = x + 5/2y + 5/2 >= y = y if(true(),x,y) = x + 5/2y + 3 >= 3 = true() if(false(),x,y) = x + 5/2y + 5/2 >= 2 = false() odd(s(0())) = 1 >= 3 = true() odd(s(s(x))) = 4x + 3 >= x = odd(x) odd(0()) = 0 >= 2 = false() problem: DPs: TRS: half(s(0())) -> 0() half(s(s(x))) -> s(half(x)) half(0()) -> 0() *(x,0()) -> 0() *(x,s(y)) -> +(*(x,y),x) f(x,0(),z) -> z f(x,s(y),z) -> if(odd(s(y)),f(x,y,*(x,z)),f(*(x,x),half(s(y)),z)) if(true(),x,y) -> x if(false(),x,y) -> y if(true(),x,y) -> true() if(false(),x,y) -> false() odd(s(0())) -> true() odd(s(s(x))) -> odd(x) odd(0()) -> false() Qed