〈a, b | aab=ba, aaaa=aa〉

Properties

• Infinite non-commutative monoid

Completion parameters

• Reduction order: right-to-left a/b

Complete rewriting system

1. a⁴ ⇒ a²
2. ba ⇒ a²b

Right Cayley graph (truncated)

Left Cayley graph (truncated)