MAYBE Initial complexity problem: 1: T: (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1 - 1, Ar_2)) [ 29 >= Ar_0 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_0 >= 30 ] (Comp: ?, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_2)) [ 19 >= Ar_1 ] (Comp: ?, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f1(Ar_0, Ar_1, Fresh_0)) [ Ar_1 >= 20 ] (Comp: ?, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1, Ar_2)) (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f3(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: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1 - 1, Ar_2)) [ 29 >= Ar_0 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_0 >= 30 ] (Comp: ?, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_2)) [ 19 >= Ar_1 ] (Comp: ?, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f1(Ar_0, Ar_1, Fresh_0)) [ Ar_1 >= 20 ] (Comp: 1, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1, Ar_2)) (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 A polynomial rank function with Pol(f2) = 1 Pol(f300) = 1 Pol(f1) = 0 Pol(f3) = 1 Pol(koat_start) = 1 orients all transitions weakly and the transition f300(Ar_0, Ar_1, Ar_2) -> Com_1(f1(Ar_0, Ar_1, Fresh_0)) [ Ar_1 >= 20 ] strictly and produces the following problem: 3: T: (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1 - 1, Ar_2)) [ 29 >= Ar_0 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1 - 1, Ar_2)) [ Ar_0 >= 30 ] (Comp: ?, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_2)) [ 19 >= Ar_1 ] (Comp: 1, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f1(Ar_0, Ar_1, Fresh_0)) [ Ar_1 >= 20 ] (Comp: 1, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1, Ar_2)) (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Applied AI with 'oct' on problem 3 to obtain the following invariants: For symbol f2: -X_2 + 19 >= 0 This yielded the following problem: 4: T: (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2) -> Com_1(f3(Ar_0, Ar_1, Ar_2)) [ 0 <= 0 ] (Comp: 1, Cost: 1) f3(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1, Ar_2)) (Comp: 1, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f1(Ar_0, Ar_1, Fresh_0)) [ Ar_1 >= 20 ] (Comp: ?, Cost: 1) f300(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1, Ar_2)) [ 19 >= Ar_1 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f300(Ar_0, Ar_1 - 1, Ar_2)) [ -Ar_1 + 19 >= 0 /\ Ar_0 >= 30 ] (Comp: ?, Cost: 1) f2(Ar_0, Ar_1, Ar_2) -> Com_1(f2(Ar_0, Ar_1 - 1, Ar_2)) [ -Ar_1 + 19 >= 0 /\ 29 >= Ar_0 ] start location: koat_start leaf cost: 0 Complexity upper bound ? Time: 1.095 sec (SMT: 1.056 sec)