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: b_7_post ≤ 0b_7_post ≤ 0b_7_0 ≤ 0b_7_0 ≤ 0
2: b_7_post ≤ 0b_7_0 ≤ 0
3: TRUE
4: TRUE

The invariants are proved as follows.

IMPACT Invariant Proof

2 Switch to Cooperation Termination Proof

We consider the following cutpoint-transitions:
1 6 1: 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 1, 2, 4, 5 using the following ranking functions, which are bounded by −13.

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

4 Location Addition

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

1* 9 1: 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.

1 7 1_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, 1_var_snapshot, 1* }.

6.1.1 Transition Removal

We remove transitions 0, 3 using the following ranking functions, which are bounded by 3.

0: 3⋅b_7_post − 4⋅x_5_0 + 4⋅y_6_0
1: 1 − 4⋅x_5_0 + 4⋅y_6_0
1_var_snapshot: −4⋅x_5_0 + 4⋅y_6_0
1*: 2 − 4⋅x_5_0 + 4⋅y_6_0

6.1.2 Transition Removal

We remove transitions 7, 9 using the following ranking functions, which are bounded by −2.

0: 0
1: −1
1_var_snapshot: −2
1*: 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 6.

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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