LTS Termination Proof

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Input

Integer Transition System

Proof

1 Invariant Updates

The following invariants are asserted.

0: −1 + b_7_post ≤ 01 − b_7_post ≤ 0−1 + b_7_0 ≤ 01 − b_7_0 ≤ 0
1: −1 + b_7_post ≤ 01 − b_7_post ≤ 0−1 + b_7_0 ≤ 01 − b_7_0 ≤ 0
2: −1 + b_7_post ≤ 01 − b_7_post ≤ 0−1 + b_7_0 ≤ 01 − b_7_0 ≤ 0
3: b_7_post ≤ 0b_7_post ≤ 0b_7_0 ≤ 0b_7_0 ≤ 0
4: b_7_post ≤ 0b_7_0 ≤ 0
5: TRUE
6: TRUE

The invariants are proved as follows.

IMPACT Invariant Proof

2 Switch to Cooperation Termination Proof

We consider the following cutpoint-transitions:
3 8 3: y_6_post + y_6_post ≤ 0y_6_posty_6_post ≤ 0y_6_0 + y_6_0 ≤ 0y_6_0y_6_0 ≤ 0x_5_post + x_5_post ≤ 0x_5_postx_5_post ≤ 0x_5_0 + x_5_0 ≤ 0x_5_0x_5_0 ≤ 0b_7_post + b_7_post ≤ 0b_7_postb_7_post ≤ 0b_7_0 + b_7_0 ≤ 0b_7_0b_7_0 ≤ 0Result_4_post + Result_4_post ≤ 0Result_4_postResult_4_post ≤ 0Result_4_0 + Result_4_0 ≤ 0Result_4_0Result_4_0 ≤ 0
and for every transition t, a duplicate t is considered.

3 Transition Removal

We remove transitions 3, 4, 6, 7 using the following ranking functions, which are bounded by −13.

6: 0
5: 0
0: 0
1: 0
2: 0
3: 0
4: 0
6: −5
5: −6
0: −7
1: −7
2: −7
3: −7
3_var_snapshot: −7
3*: −7
4: −11

4 Location Addition

The following skip-transition is inserted and corresponding redirections w.r.t. the old location are performed.

3* 11 3: y_6_post + y_6_post ≤ 0y_6_posty_6_post ≤ 0y_6_0 + y_6_0 ≤ 0y_6_0y_6_0 ≤ 0x_5_post + x_5_post ≤ 0x_5_postx_5_post ≤ 0x_5_0 + x_5_0 ≤ 0x_5_0x_5_0 ≤ 0b_7_post + b_7_post ≤ 0b_7_postb_7_post ≤ 0b_7_0 + b_7_0 ≤ 0b_7_0b_7_0 ≤ 0Result_4_post + Result_4_post ≤ 0Result_4_postResult_4_post ≤ 0Result_4_0 + Result_4_0 ≤ 0Result_4_0Result_4_0 ≤ 0

5 Location Addition

The following skip-transition is inserted and corresponding redirections w.r.t. the old location are performed.

3 9 3_var_snapshot: y_6_post + y_6_post ≤ 0y_6_posty_6_post ≤ 0y_6_0 + y_6_0 ≤ 0y_6_0y_6_0 ≤ 0x_5_post + x_5_post ≤ 0x_5_postx_5_post ≤ 0x_5_0 + x_5_0 ≤ 0x_5_0x_5_0 ≤ 0b_7_post + b_7_post ≤ 0b_7_postb_7_post ≤ 0b_7_0 + b_7_0 ≤ 0b_7_0b_7_0 ≤ 0Result_4_post + Result_4_post ≤ 0Result_4_postResult_4_post ≤ 0Result_4_0 + Result_4_0 ≤ 0Result_4_0Result_4_0 ≤ 0

6 SCC Decomposition

We consider subproblems for each of the 1 SCC(s) of the program graph.

6.1 SCC Subproblem 1/1

Here we consider the SCC { 0, 1, 2, 3, 3_var_snapshot, 3* }.

6.1.1 Transition Removal

We remove transitions 0, 5 using the following ranking functions, which are bounded by 1.

0: 1 − 2⋅x_5_0 + 2⋅y_6_0
1: −2⋅x_5_0 + 2⋅y_6_0
2: −2⋅x_5_0 + 2⋅y_6_0
3: 1 − 2⋅x_5_0 + 2⋅y_6_0
3_var_snapshot: −2⋅x_5_0 + 2⋅y_6_0
3*: 2 − 2⋅x_5_0 + 2⋅y_6_0

6.1.2 Transition Removal

We remove transitions 9, 11, 1, 2 using the following ranking functions, which are bounded by −2.

0: 0
1: 1 + b_7_0
2: b_7_0
3: −1
3_var_snapshot: −2
3*: 0

6.1.3 Splitting Cut-Point Transitions

We consider 1 subproblems corresponding to sets of cut-point transitions as follows.

6.1.3.1 Cut-Point Subproblem 1/1

Here we consider cut-point transition 8.

6.1.3.1.1 Splitting Cut-Point Transitions

There remain no cut-point transition to consider. Hence the cooperation termination is trivial.

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