WORST_CASE(?, O(EXP)) Initial complexity problem: 1: T: (Comp: ?, Cost: 1) f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2)) (Comp: ?, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ] (Comp: ?, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ] (Comp: ?, Cost: 1) h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Repeatedly propagating knowledge in problem 1 produces the following problem: 2: T: (Comp: 1, Cost: 1) f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2)) (Comp: ?, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ] (Comp: ?, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ] (Comp: ?, Cost: 1) h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(f) = 1 Pol(g) = 1 Pol(h) = 0 Pol(koat_start) = 1 orients all transitions weakly and the transition g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ] strictly and produces the following problem: 3: T: (Comp: 1, Cost: 1) f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2)) (Comp: ?, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ] (Comp: 1, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ] (Comp: ?, Cost: 1) h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(f) = V_3 Pol(g) = V_3 Pol(h) = V_3 Pol(koat_start) = V_3 orients all transitions weakly and the transition g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ] strictly and produces the following problem: 4: T: (Comp: 1, Cost: 1) f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2)) (Comp: Ar_2, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ] (Comp: 1, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ] (Comp: ?, Cost: 1) h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(h) = V_2 and size complexities S("koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ]", 0-0) = Ar_0 S("koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ]", 0-1) = Ar_1 S("koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ]", 0-2) = Ar_2 S("h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ]", 0-0) = pow(2, 2*Ar_2) + 1 S("h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ]", 0-1) = pow(2, 2*Ar_2) + 1 S("h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ]", 0-2) = Ar_2 S("g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ]", 0-0) = pow(2, 2*Ar_2) + 1 S("g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ]", 0-1) = pow(2, 2*Ar_2) + 1 S("g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ]", 0-2) = Ar_2 S("g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ]", 0-0) = pow(2, 2*Ar_2) S("g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ]", 0-1) = pow(2, 2*Ar_2) S("g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ]", 0-2) = Ar_2 S("f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2))", 0-0) = 1 S("f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2))", 0-1) = 1 S("f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2))", 0-2) = Ar_2 orients the transitions h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ] weakly and the transition h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ] strictly and produces the following problem: 5: T: (Comp: 1, Cost: 1) f(Ar_0, Ar_1, Ar_2) -> Com_1(g(1, 1, Ar_2)) (Comp: Ar_2, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(g(Ar_0 + Ar_1, Ar_0 + Ar_1, Ar_2 - 1)) [ Ar_2 > 0 ] (Comp: 1, Cost: 1) g(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1, Ar_2)) [ Ar_2 <= 0 ] (Comp: pow(2, 2*Ar_2) + 1, Cost: 1) h(Ar_0, Ar_1, Ar_2) -> Com_1(h(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_1 > 0 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Complexity upper bound pow(2, 2*Ar_2) + Ar_2 + 3 Time: 1.163 sec (SMT: 1.131 sec)