MAYBE Initial complexity problem: 1: T: (Comp: ?, Cost: 1) f1(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_1 + 1)) [ Ar_0 >= Ar_1 /\ Ar_0 >= 1 /\ Ar_1 >= 1 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ Ar_1 >= Ar_2 + 1 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ Ar_2 >= Ar_1 + 1 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, 0)) [ Ar_0 + 1 >= 0 /\ Ar_2 >= 1 /\ Ar_2 >= Ar_0 + 1 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_2 + 1)) [ Ar_0 >= Ar_2 /\ Ar_2 + 1 >= 0 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f1(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) f1(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_1 + 1)) [ Ar_0 >= Ar_1 /\ Ar_0 >= 1 /\ Ar_1 >= 1 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ Ar_1 >= Ar_2 + 1 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ Ar_2 >= Ar_1 + 1 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, 0)) [ Ar_0 + 1 >= 0 /\ Ar_2 >= 1 /\ Ar_2 >= Ar_0 + 1 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_2 + 1)) [ Ar_0 >= Ar_2 /\ Ar_2 + 1 >= 0 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f1(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Applied AI with 'oct' on problem 2 to obtain the following invariants: For symbol f2: X_1 - X_3 + 1 >= 0 /\ X_1 - X_2 >= 0 /\ X_2 - 1 >= 0 /\ X_1 + X_2 - 2 >= 0 /\ X_1 - 1 >= 0 For symbol f3: X_1 - X_3 + 1 >= 0 /\ X_1 - X_2 >= 0 /\ X_2 - 1 >= 0 /\ X_1 + X_2 - 2 >= 0 /\ X_1 - 1 >= 0 This yielded the following problem: 3: T: (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f1(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_2 + 1)) [ Ar_0 - Ar_2 + 1 >= 0 /\ Ar_0 - Ar_1 >= 0 /\ Ar_1 - 1 >= 0 /\ Ar_0 + Ar_1 - 2 >= 0 /\ Ar_0 - 1 >= 0 /\ Ar_0 >= Ar_2 /\ Ar_2 + 1 >= 0 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, 0)) [ Ar_0 - Ar_2 + 1 >= 0 /\ Ar_0 - Ar_1 >= 0 /\ Ar_1 - 1 >= 0 /\ Ar_0 + Ar_1 - 2 >= 0 /\ Ar_0 - 1 >= 0 /\ Ar_0 + 1 >= 0 /\ Ar_2 >= 1 /\ Ar_2 >= Ar_0 + 1 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ Ar_0 - Ar_2 + 1 >= 0 /\ Ar_0 - Ar_1 >= 0 /\ Ar_1 - 1 >= 0 /\ Ar_0 + Ar_1 - 2 >= 0 /\ Ar_0 - 1 >= 0 /\ Ar_2 >= Ar_1 + 1 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ Ar_0 - Ar_2 + 1 >= 0 /\ Ar_0 - Ar_1 >= 0 /\ Ar_1 - 1 >= 0 /\ Ar_0 + Ar_1 - 2 >= 0 /\ Ar_0 - 1 >= 0 /\ Ar_1 >= Ar_2 + 1 ] (Comp: 1, Cost: 1) f1(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_1 + 1)) [ Ar_0 >= Ar_1 /\ Ar_0 >= 1 /\ Ar_1 >= 1 ] start location: koat_start leaf cost: 0 Complexity upper bound ? Time: 1.239 sec (SMT: 1.192 sec)