WORST_CASE(?, O(n^1)) Initial complexity problem: 1: T: (Comp: ?, Cost: 1) f0(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0, Ar_1, Ar_2)) (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f6(Ar_0, Ar_1, Ar_2) -> Com_1(f4(Ar_0, Ar_1, 1)) [ Ar_0 >= 1 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ 0 >= Ar_2 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ Ar_2 >= 2 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ Ar_0 >= 1 /\ 0 >= Ar_2 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ Ar_0 >= 1 /\ Ar_2 >= 2 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ 0 >= Ar_0 + 1 /\ Ar_2 = 1 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: ?, Cost: 1) f5(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ 0 >= Ar_0 + 1 /\ Ar_2 = 1 ] (Comp: ?, Cost: 1) f5(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f6(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Testing for reachability in the complexity graph removes the following transitions from problem 1: f0(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0, Ar_1, Ar_2)) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ Ar_2 >= 2 ] f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ Ar_0 >= 1 /\ 0 >= Ar_2 ] f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ Ar_0 >= 1 /\ Ar_2 >= 2 ] f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ 0 >= Ar_0 + 1 /\ Ar_2 = 1 ] f5(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ 0 >= Ar_0 + 1 /\ Ar_2 = 1 ] f5(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] We thus obtain the following problem: 2: T: (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ 0 >= Ar_2 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: ?, Cost: 1) f6(Ar_0, Ar_1, Ar_2) -> Com_1(f4(Ar_0, Ar_1, 1)) [ Ar_0 >= 1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f6(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Repeatedly propagating knowledge in problem 2 produces the following problem: 3: T: (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ 0 >= Ar_2 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: 1, Cost: 1) f6(Ar_0, Ar_1, Ar_2) -> Com_1(f4(Ar_0, Ar_1, 1)) [ Ar_0 >= 1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f6(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(f4) = 1 Pol(f7) = 0 Pol(f3) = 1 Pol(f6) = 1 Pol(koat_start) = 1 orients all transitions weakly and the transition f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] strictly and produces the following problem: 4: T: (Comp: 1, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ 0 >= Ar_2 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: 1, Cost: 1) f6(Ar_0, Ar_1, Ar_2) -> Com_1(f4(Ar_0, Ar_1, 1)) [ Ar_0 >= 1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f6(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(f4) = 1 Pol(f7) = 0 Pol(f3) = 1 Pol(f6) = 1 Pol(koat_start) = 1 orients all transitions weakly and the transition f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] strictly and produces the following problem: 5: T: (Comp: 1, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ 0 >= Ar_2 ] (Comp: 1, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: 1, Cost: 1) f6(Ar_0, Ar_1, Ar_2) -> Com_1(f4(Ar_0, Ar_1, 1)) [ Ar_0 >= 1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f6(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(f4) = V_1 Pol(f7) = 0 Pol(f3) = -V_1 Pol(f6) = V_1 Pol(koat_start) = V_1 orients all transitions weakly and the transition f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] strictly and produces the following problem: 6: T: (Comp: 1, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ 0 >= Ar_2 ] (Comp: 1, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] (Comp: Ar_0, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: 1, Cost: 1) f6(Ar_0, Ar_1, Ar_2) -> Com_1(f4(Ar_0, Ar_1, 1)) [ Ar_0 >= 1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f6(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Repeatedly propagating knowledge in problem 6 produces the following problem: 7: T: (Comp: 1, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_0, Ar_2)) [ Ar_0 = 0 ] (Comp: Ar_0, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f4(-Ar_0 - 1, Ar_1, 1)) [ 0 >= Ar_0 + 1 /\ 0 >= Ar_2 ] (Comp: 1, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f7(0, Fresh_1, Ar_2)) [ Ar_0 = 0 ] (Comp: Ar_0, Cost: 1) f4(Ar_0, Ar_1, Ar_2) -> Com_1(f3(-Ar_0 + 1, Ar_1, 0)) [ Ar_0 >= 1 /\ Ar_2 = 1 ] (Comp: 1, Cost: 1) f6(Ar_0, Ar_1, Ar_2) -> Com_1(f4(Ar_0, Ar_1, 1)) [ Ar_0 >= 1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f6(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Complexity upper bound 2*Ar_0 + 3 Time: 1.060 sec (SMT: 1.033 sec)