NO Initial ITS Start location: l4 Program variables: i^0 j^0 ret_pair5^0 0: l0 -> l1 : i^0'=i^post1, j^0'=j^post1, ret_pair5^0'=ret_pair5^post1, (0 == 0 /\ -2+j^post1-j^0 == 0 /\ -1-i^0+i^post1 == 0), cost: 1 1: l0 -> l2 : i^0'=i^post2, j^0'=j^post2, ret_pair5^0'=ret_pair5^post2, (ret_pair5^0-ret_pair5^post2 == 0 /\ -j^post2+j^0 == 0 /\ i^0-i^post2 == 0), cost: 1 2: l1 -> l0 : i^0'=i^post3, j^0'=j^post3, ret_pair5^0'=ret_pair5^post3, (ret_pair5^0-ret_pair5^post3 == 0 /\ -j^post3+j^0 == 0 /\ i^0-i^post3 == 0), cost: 1 3: l3 -> l1 : i^0'=i^post4, j^0'=j^post4, ret_pair5^0'=ret_pair5^post4, (j^post4 == 0 /\ ret_pair5^0-ret_pair5^post4 == 0 /\ i^post4 == 0), cost: 1 4: l4 -> l3 : i^0'=i^post5, j^0'=j^post5, ret_pair5^0'=ret_pair5^post5, (i^0-i^post5 == 0 /\ j^0-j^post5 == 0 /\ ret_pair5^0-ret_pair5^post5 == 0), cost: 1 Chained Linear Paths Start location: l4 Program variables: i^0 j^0 ret_pair5^0 0: l0 -> l1 : i^0'=i^post1, j^0'=j^post1, ret_pair5^0'=ret_pair5^post1, (0 == 0 /\ -2+j^post1-j^0 == 0 /\ -1-i^0+i^post1 == 0), cost: 1 1: l0 -> l2 : i^0'=i^post2, j^0'=j^post2, ret_pair5^0'=ret_pair5^post2, (ret_pair5^0-ret_pair5^post2 == 0 /\ -j^post2+j^0 == 0 /\ i^0-i^post2 == 0), cost: 1 2: l1 -> l0 : i^0'=i^post3, j^0'=j^post3, ret_pair5^0'=ret_pair5^post3, (ret_pair5^0-ret_pair5^post3 == 0 /\ -j^post3+j^0 == 0 /\ i^0-i^post3 == 0), cost: 1 5: l4 -> l1 : i^0'=i^post4, j^0'=j^post4, ret_pair5^0'=ret_pair5^post4, (i^0-i^post5 == 0 /\ j^post4 == 0 /\ j^0-j^post5 == 0 /\ ret_pair5^0-ret_pair5^post5 == 0 /\ i^post4 == 0 /\ ret_pair5^post5-ret_pair5^post4 == 0), cost: 1 Eliminating location l3 by chaining: Applied chaining First rule: l4 -> l3 : i^0'=i^post5, j^0'=j^post5, ret_pair5^0'=ret_pair5^post5, (i^0-i^post5 == 0 /\ j^0-j^post5 == 0 /\ ret_pair5^0-ret_pair5^post5 == 0), cost: 1 Second rule: l3 -> l1 : i^0'=i^post4, j^0'=j^post4, ret_pair5^0'=ret_pair5^post4, (j^post4 == 0 /\ ret_pair5^0-ret_pair5^post4 == 0 /\ i^post4 == 0), cost: 1 New rule: l4 -> l1 : i^0'=i^post4, j^0'=j^post4, ret_pair5^0'=ret_pair5^post4, (i^0-i^post5 == 0 /\ j^post4 == 0 /\ j^0-j^post5 == 0 /\ ret_pair5^0-ret_pair5^post5 == 0 /\ i^post4 == 0 /\ ret_pair5^post5-ret_pair5^post4 == 0), cost: 1 Applied deletion Removed the following rules: 3 4 Simplified Transitions Start location: l4 Program variables: i^0 j^0 ret_pair5^0 6: l0 -> l1 : i^0'=1+i^0, j^0'=2+j^0, ret_pair5^0'=ret_pair5^post1, T, cost: 1 7: l0 -> l2 : T, cost: 1 8: l1 -> l0 : T, cost: 1 9: l4 -> l1 : i^0'=0, j^0'=0, T, cost: 1 Propagated Equalities Original rule: l0 -> l1 : i^0'=i^post1, j^0'=j^post1, ret_pair5^0'=ret_pair5^post1, (0 == 0 /\ -2+j^post1-j^0 == 0 /\ -1-i^0+i^post1 == 0), cost: 1 New rule: l0 -> l1 : i^0'=1+i^0, j^0'=2+j^0, ret_pair5^0'=ret_pair5^post1, 0 == 0, cost: 1 propagated equality j^post1 = 2+j^0 propagated equality i^post1 = 1+i^0 Simplified Guard Original rule: l0 -> l1 : i^0'=1+i^0, j^0'=2+j^0, ret_pair5^0'=ret_pair5^post1, 0 == 0, cost: 1 New rule: l0 -> l1 : i^0'=1+i^0, j^0'=2+j^0, ret_pair5^0'=ret_pair5^post1, T, cost: 1 Propagated Equalities Original rule: l0 -> l2 : i^0'=i^post2, j^0'=j^post2, ret_pair5^0'=ret_pair5^post2, (ret_pair5^0-ret_pair5^post2 == 0 /\ -j^post2+j^0 == 0 /\ i^0-i^post2 == 0), cost: 1 New rule: l0 -> l2 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, 0 == 0, cost: 1 propagated equality ret_pair5^post2 = ret_pair5^0 propagated equality j^post2 = j^0 propagated equality i^post2 = i^0 Simplified Guard Original rule: l0 -> l2 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, 0 == 0, cost: 1 New rule: l0 -> l2 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, T, cost: 1 Removed Trivial Updates Original rule: l0 -> l2 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, T, cost: 1 New rule: l0 -> l2 : T, cost: 1 Propagated Equalities Original rule: l1 -> l0 : i^0'=i^post3, j^0'=j^post3, ret_pair5^0'=ret_pair5^post3, (ret_pair5^0-ret_pair5^post3 == 0 /\ -j^post3+j^0 == 0 /\ i^0-i^post3 == 0), cost: 1 New rule: l1 -> l0 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, 0 == 0, cost: 1 propagated equality ret_pair5^post3 = ret_pair5^0 propagated equality j^post3 = j^0 propagated equality i^post3 = i^0 Simplified Guard Original rule: l1 -> l0 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, 0 == 0, cost: 1 New rule: l1 -> l0 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, T, cost: 1 Removed Trivial Updates Original rule: l1 -> l0 : i^0'=i^0, j^0'=j^0, ret_pair5^0'=ret_pair5^0, T, cost: 1 New rule: l1 -> l0 : T, cost: 1 Propagated Equalities Original rule: l4 -> l1 : i^0'=i^post4, j^0'=j^post4, ret_pair5^0'=ret_pair5^post4, (i^0-i^post5 == 0 /\ j^post4 == 0 /\ j^0-j^post5 == 0 /\ ret_pair5^0-ret_pair5^post5 == 0 /\ i^post4 == 0 /\ ret_pair5^post5-ret_pair5^post4 == 0), cost: 1 New rule: l4 -> l1 : i^0'=0, j^0'=0, ret_pair5^0'=ret_pair5^post5, (0 == 0 /\ i^0-i^post5 == 0 /\ j^0-j^post5 == 0 /\ ret_pair5^0-ret_pair5^post5 == 0), cost: 1 propagated equality j^post4 = 0 propagated equality i^post4 = 0 propagated equality ret_pair5^post4 = ret_pair5^post5 Propagated Equalities Original rule: l4 -> l1 : i^0'=0, j^0'=0, ret_pair5^0'=ret_pair5^post5, (0 == 0 /\ i^0-i^post5 == 0 /\ j^0-j^post5 == 0 /\ ret_pair5^0-ret_pair5^post5 == 0), cost: 1 New rule: l4 -> l1 : i^0'=0, j^0'=0, ret_pair5^0'=ret_pair5^0, 0 == 0, cost: 1 propagated equality i^post5 = i^0 propagated equality j^post5 = j^0 propagated equality ret_pair5^post5 = ret_pair5^0 Simplified Guard Original rule: l4 -> l1 : i^0'=0, j^0'=0, ret_pair5^0'=ret_pair5^0, 0 == 0, cost: 1 New rule: l4 -> l1 : i^0'=0, j^0'=0, ret_pair5^0'=ret_pair5^0, T, cost: 1 Removed Trivial Updates Original rule: l4 -> l1 : i^0'=0, j^0'=0, ret_pair5^0'=ret_pair5^0, T, cost: 1 New rule: l4 -> l1 : i^0'=0, j^0'=0, T, cost: 1 Step with 9 Trace 9[T] Blocked [{}, {}] Step with 8 Trace 9[T], 8[T] Blocked [{}, {}, {}] Step with 7 Trace 9[T], 8[T], 7[T] Blocked [{}, {}, {}, {}] Backtrack Trace 9[T], 8[T] Blocked [{}, {}, {7[T]}] Step with 6 Trace 9[T], 8[T], 6[T] Blocked [{}, {}, {7[T]}, {}] Nonterm Start location: l4 Program variables: i^0 j^0 ret_pair5^0 6: l0 -> l1 : i^0'=1+i^0, j^0'=2+j^0, ret_pair5^0'=ret_pair5^post1, T, cost: 1 7: l0 -> l2 : T, cost: 1 8: l1 -> l0 : T, cost: 1 10: l1 -> LoAT_sink : -1+n >= 0, cost: NONTERM 11: l1 -> l1 : i^0'=n+i^0, j^0'=2*n+j^0, ret_pair5^0'=ret_pair5^post1, -1+n >= 0, cost: 1 9: l4 -> l1 : i^0'=0, j^0'=0, T, cost: 1 Certificate of Non-Termination Original rule: l1 -> l1 : i^0'=1+i^0, j^0'=2+j^0, ret_pair5^0'=ret_pair5^post1, T, cost: 1 New rule: l1 -> LoAT_sink : -1+n >= 0, cost: NONTERM Replacement map: {} Loop Acceleration Original rule: l1 -> l1 : i^0'=1+i^0, j^0'=2+j^0, ret_pair5^0'=ret_pair5^post1, T, cost: 1 New rule: l1 -> l1 : i^0'=n+i^0, j^0'=2*n+j^0, ret_pair5^0'=ret_pair5^post1, -1+n >= 0, cost: 1 Replacement map: {} Step with 10 Trace 9[T], 10[-1+n >= 0] Blocked [{}, {}, {10[T]}] Refute Counterexample [ i^0=0 j^0=0 ret_pair5^0=0 ] 9 [ i^0=i^0 j^0=j^0 ret_pair5^0=0 ] 10 NO Build SHA: a05f16bf13df659c382799650051f91bf6828c7b