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 Locally confluent and terminating

Confluence is proven by showing local confluence and termination.

1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[a3] = 0
[b1] = 0
[b2] = 0
[a2] = 0
[c4] = 0
[a1] = 0
[c3] = 0
[a5] = 1
[b5] = 0
[a4] = 0
[b4] = 0
[c5] = 0
[b3] = 0
[c1] = 0
the rules
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
b5 b6
c5 b6
remain.

1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[a3] = 0
[b1] = 0
[b2] = 0
[a2] = 0
[c4] = 0
[a1] = 0
[c3] = 0
[b5] = 0
[a4] = 4
[b4] = 0
[c5] = 0
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
b1 b2
c1 c2
a2 b2
a2 c2
b2 b3
c2 c3
a3 b3
a3 c3
b3 b4
c3 c4
b4 b5
c4 c5
b5 b6
c5 b6
remain.

1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[a3] = 1
[b1] = 0
[b2] = 0
[a2] = 0
[c4] = 0
[a1] = 0
[c3] = 0
[b5] = 0
[b4] = 0
[c5] = 0
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
b1 b2
c1 c2
a2 b2
a2 c2
b2 b3
c2 c3
b3 b4
c3 c4
b4 b5
c4 c5
b5 b6
c5 b6
remain.

1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[b1] = 0
[b2] = 0
[a2] = 4
[c4] = 0
[a1] = 0
[c3] = 0
[b5] = 0
[b4] = 0
[c5] = 0
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
b1 b2
c1 c2
b2 b3
c2 c3
b3 b4
c3 c4
b4 b5
c4 c5
b5 b6
c5 b6
remain.

1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 4
[b6] = 0
[b1] = 4
[b2] = 4
[c4] = 1
[a1] = 4
[c3] = 1
[b5] = 0
[b4] = 0
[c5] = 0
[b3] = 4
[c1] = 4
the rules
a1 b1
a1 c1
b1 b2
c1 c2
b2 b3
c3 c4
b4 b5
b5 b6
c5 b6
remain.

1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[b1] = 0
[b2] = 0
[c4] = 0
[a1] = 0
[c3] = 0
[b5] = 0
[b4] = 0
[c5] = 1
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
b1 b2
c1 c2
b2 b3
c3 c4
b4 b5
b5 b6
remain.

1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b6] = 0
[b1] = 0
[b2] = 0
[c4] = 0
[a1] = 0
[c3] = 0
[b5] = 4
[b4] = 4
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
b1 b2
c1 c2
b2 b3
c3 c4
b4 b5
remain.

1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b1] = 0
[b2] = 0
[c4] = 0
[a1] = 0
[c3] = 0
[b5] = 0
[b4] = 1
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
b1 b2
c1 c2
b2 b3
c3 c4
remain.

1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b1] = 0
[b2] = 0
[c4] = 0
[a1] = 0
[c3] = 1
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
b1 b2
c1 c2
b2 b3
remain.

1.1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 4
[b1] = 4
[b2] = 0
[a1] = 4
[b3] = 0
[c1] = 4
the rules
a1 b1
a1 c1
c1 c2
b2 b3
remain.

1.1.1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b1] = 0
[b2] = 1
[a1] = 0
[b3] = 0
[c1] = 0
the rules
a1 b1
a1 c1
c1 c2
remain.

1.1.1.1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b1] = 4
[a1] = 4
[c1] = 0
the rules
a1 b1
c1 c2
remain.

1.1.1.1.1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[c2] = 0
[b1] = 0
[a1] = 0
[c1] = 1
the rule
a1 b1
remains.

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1 Rule Removal

Using the linear polynomial interpretation over the naturals
[b1] = 0
[a1] = 1
all rules could be removed.

1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1 R is empty

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

1.2 Local Confluence Proof

All critical pairs are joinable which can be seen by computing normal forms of all critical pairs.

Tool configuration

csi