MAYBE Initial complexity problem: 1: T: (Comp: ?, Cost: 1) f21(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f29(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) [ 0 >= Ar_0 ] (Comp: ?, Cost: 1) f41(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f41(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) (Comp: ?, Cost: 1) f43(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f46(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) (Comp: ?, Cost: 1) f29(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f41(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) [ Ar_0 >= 1 ] (Comp: ?, Cost: 1) f29(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f41(Ar_0, Ar_1, Fresh_7, 0, Fresh_7, Fresh_7, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) [ 0 >= Ar_0 /\ Ar_1 + 999 >= Fresh_7 ] (Comp: ?, Cost: 1) f29(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f41(1, Ar_1, Fresh_6, 0, Fresh_6, Fresh_6, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) [ 0 >= Ar_0 /\ Fresh_6 >= Ar_1 + 1000 ] (Comp: ?, Cost: 1) f21(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f29(0, Fresh_5, Fresh_5, Ar_3, Ar_4, Ar_5, 0, Fresh_5, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) [ Ar_0 >= 1 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f21(1, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Fresh_4, Fresh_4, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) [ 0 >= Fresh_4 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f21(1, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Fresh_2, 0, 1, Fresh_3, Fresh_3, Fresh_3, Fresh_3)) [ Fresh_2 >= 1 /\ Fresh_3 >= 1 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f41(1, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Fresh_0, 0, 1, Fresh_1, Fresh_1, Fresh_1, Fresh_1)) [ Fresh_0 >= 1 /\ 0 >= Fresh_1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14) -> Com_1(f0(Ar_0, Ar_1, Ar_2, Ar_3, Ar_4, Ar_5, Ar_6, Ar_7, Ar_8, Ar_9, Ar_10, Ar_11, Ar_12, Ar_13, Ar_14)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Slicing away variables that do not contribute to conditions from problem 1 leaves variables [Ar_0, Ar_1]. We thus obtain the following problem: 2: T: (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1) -> Com_1(f0(Ar_0, Ar_1)) [ 0 <= 0 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ Fresh_0 >= 1 /\ 0 >= Fresh_1 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ Fresh_2 >= 1 /\ Fresh_3 >= 1 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ 0 >= Fresh_4 ] (Comp: ?, Cost: 1) f21(Ar_0, Ar_1) -> Com_1(f29(0, Fresh_5)) [ Ar_0 >= 1 ] (Comp: ?, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ 0 >= Ar_0 /\ Fresh_6 >= Ar_1 + 1000 ] (Comp: ?, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) [ 0 >= Ar_0 /\ Ar_1 + 999 >= Fresh_7 ] (Comp: ?, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) [ Ar_0 >= 1 ] (Comp: ?, Cost: 1) f43(Ar_0, Ar_1) -> Com_1(f46(Ar_0, Ar_1)) (Comp: ?, Cost: 1) f41(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) (Comp: ?, Cost: 1) f21(Ar_0, Ar_1) -> Com_1(f29(Ar_0, Ar_1)) [ 0 >= Ar_0 ] start location: koat_start leaf cost: 0 Testing for reachability in the complexity graph removes the following transitions from problem 2: f29(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) [ Ar_0 >= 1 ] f43(Ar_0, Ar_1) -> Com_1(f46(Ar_0, Ar_1)) f21(Ar_0, Ar_1) -> Com_1(f29(Ar_0, Ar_1)) [ 0 >= Ar_0 ] We thus obtain the following problem: 3: T: (Comp: ?, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) [ 0 >= Ar_0 /\ Ar_1 + 999 >= Fresh_7 ] (Comp: ?, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ 0 >= Ar_0 /\ Fresh_6 >= Ar_1 + 1000 ] (Comp: ?, Cost: 1) f21(Ar_0, Ar_1) -> Com_1(f29(0, Fresh_5)) [ Ar_0 >= 1 ] (Comp: ?, Cost: 1) f41(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) (Comp: ?, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ 0 >= Fresh_4 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ Fresh_2 >= 1 /\ Fresh_3 >= 1 ] (Comp: ?, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ Fresh_0 >= 1 /\ 0 >= Fresh_1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1) -> Com_1(f0(Ar_0, Ar_1)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Repeatedly propagating knowledge in problem 3 produces the following problem: 4: T: (Comp: 2, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) [ 0 >= Ar_0 /\ Ar_1 + 999 >= Fresh_7 ] (Comp: 2, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ 0 >= Ar_0 /\ Fresh_6 >= Ar_1 + 1000 ] (Comp: 2, Cost: 1) f21(Ar_0, Ar_1) -> Com_1(f29(0, Fresh_5)) [ Ar_0 >= 1 ] (Comp: ?, Cost: 1) f41(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) (Comp: 1, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ 0 >= Fresh_4 ] (Comp: 1, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ Fresh_2 >= 1 /\ Fresh_3 >= 1 ] (Comp: 1, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ Fresh_0 >= 1 /\ 0 >= Fresh_1 ] (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1) -> Com_1(f0(Ar_0, Ar_1)) [ 0 <= 0 ] start location: koat_start leaf cost: 0 Applied AI with 'oct' on problem 4 to obtain the following invariants: For symbol f21: -X_1 + 1 >= 0 /\ X_1 - 1 >= 0 For symbol f29: -X_1 >= 0 /\ X_1 >= 0 For symbol f41: -X_1 + 1 >= 0 /\ X_1 >= 0 This yielded the following problem: 5: T: (Comp: 1, Cost: 0) koat_start(Ar_0, Ar_1) -> Com_1(f0(Ar_0, Ar_1)) [ 0 <= 0 ] (Comp: 1, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ Fresh_0 >= 1 /\ 0 >= Fresh_1 ] (Comp: 1, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ Fresh_2 >= 1 /\ Fresh_3 >= 1 ] (Comp: 1, Cost: 1) f0(Ar_0, Ar_1) -> Com_1(f21(1, Ar_1)) [ 0 >= Fresh_4 ] (Comp: ?, Cost: 1) f41(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) [ -Ar_0 + 1 >= 0 /\ Ar_0 >= 0 ] (Comp: 2, Cost: 1) f21(Ar_0, Ar_1) -> Com_1(f29(0, Fresh_5)) [ -Ar_0 + 1 >= 0 /\ Ar_0 - 1 >= 0 /\ Ar_0 >= 1 ] (Comp: 2, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(1, Ar_1)) [ -Ar_0 >= 0 /\ Ar_0 >= 0 /\ 0 >= Ar_0 /\ Fresh_6 >= Ar_1 + 1000 ] (Comp: 2, Cost: 1) f29(Ar_0, Ar_1) -> Com_1(f41(Ar_0, Ar_1)) [ -Ar_0 >= 0 /\ Ar_0 >= 0 /\ 0 >= Ar_0 /\ Ar_1 + 999 >= Fresh_7 ] start location: koat_start leaf cost: 0 Complexity upper bound ? Time: 1.336 sec (SMT: 1.286 sec)