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 → b5
a5 → c5
b5 → b6
c5 → c6
a6 → b6
a6 → c6
b6 → b7
c6 → b7
b7 → b1
b7 → c1

Proof

1 Redundant Rules Transformation

To prove that the TRS is (non-)confluent, we show (non-)confluence of the following modified system:

b7 → c1
b7 → b1
c6 → b7
b6 → b7
a6 → c6
a6 → b6
c5 → c6
b5 → b6
a5 → c5
a5 → b5
c4 → c5
b4 → b5
a4 → c4
a4 → b4
c3 → c4
b3 → b4
a3 → c3
a3 → b3
c2 → c3
b2 → b3
a2 → c2
a2 → b2
c1 → c2
b1 → b2
a1 → c1
a1 → b1
b1 → b7
c1 → b7
b2 → b7
c2 → b7
b3 → b7
c3 → b7
b4 → b7
c4 → b7
b5 → b7
c5 → b7

All redundant rules that were added or removed can be simulated in 6 steps .

1.1 Strongly closed

Confluence is proven since the TRS is strongly closed. The joins can be performed within 7 step(s).

Tool configuration

csi