YES Confluence Proof

Confluence Proof

by csi

Input

The rewrite relation of the following TRS is considered.

a1 b1
a1 c1
b1 b2
c1 c2
a2 b2
a2 c2
b2 b3
c2 c3
a3 b3
a3 c3
b3 b4
c3 c4
a4 b4
a4 c4
b4 b5
c4 c5
a5 b6
b5 b6
c5 b6

Proof

1 Critical Pair Closing System

Confluence is proven using the following terminating critical-pair-closing-system R:

b1 b2
b2 b3
b3 b4
b4 b5
b5 b6
c1 c2
c2 c3
c3 c4
c4 c5
c5 b6

1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 4
[b6] = 0
[b1] = 0
[b2] = 0
[c4] = 0
[c3] = 0
[b5] = 0
[b4] = 0
[c5] = 0
[b3] = 0
[c1] = 4
the rules
b1 b2
b2 b3
b3 b4
b4 b5
b5 b6
c1 c2
c3 c4
c4 c5
c5 b6
remain.

1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[b1] = 0
[b2] = 0
[c4] = 4
[c3] = 4
[b5] = 0
[b4] = 0
[c5] = 0
[b3] = 0
[c1] = 0
the rules
b1 b2
b2 b3
b3 b4
b4 b5
b5 b6
c1 c2
c3 c4
c5 b6
remain.

1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[b1] = 0
[b2] = 0
[c4] = 0
[c3] = 0
[b5] = 0
[b4] = 0
[c5] = 1
[b3] = 0
[c1] = 0
the rules
b1 b2
b2 b3
b3 b4
b4 b5
b5 b6
c1 c2
c3 c4
remain.

1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[b1] = 0
[b2] = 0
[c4] = 0
[c3] = 1
[b5] = 0
[b4] = 0
[b3] = 0
[c1] = 0
the rules
b1 b2
b2 b3
b3 b4
b4 b5
b5 b6
c1 c2
remain.

1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[b1] = 0
[b2] = 0
[b5] = 0
[b4] = 0
[b3] = 0
[c1] = 1
the rules
b1 b2
b2 b3
b3 b4
b4 b5
b5 b6
remain.

1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[b6] = 0
[b1] = 4
[b2] = 4
[b5] = 0
[b4] = 0
[b3] = 4
the rules
b1 b2
b2 b3
b4 b5
b5 b6
remain.

1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[b6] = 0
[b1] = 0
[b2] = 0
[b5] = 4
[b4] = 4
[b3] = 0
the rules
b1 b2
b2 b3
b4 b5
remain.

1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[b1] = 0
[b2] = 0
[b5] = 0
[b4] = 1
[b3] = 0
the rules
b1 b2
b2 b3
remain.

1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[b1] = 4
[b2] = 4
[b3] = 0
the rule
b1 b2
remains.

1.1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[b1] = 1
[b2] = 0
all rules could be removed.

1.1.1.1.1.1.1.1.1.1.1.1 R is empty

There are no rules in the TRS. Hence, it is terminating.

Tool configuration

csi