〈a, b | abba=b, bbbbb=b〉

Properties

• Infinite commutative monoid
• Isomorphic to commutative presentation: 〈a, b | 4b=2a+b, 2a+2b=b, 4a+b=3b〉
• Grothendieck group is ℤ₈

Completion parameters

• Reduction order: left-to-right b/a

Complete rewriting system

1. b⁵ ⇒ b
2. ba ⇒ ab
3. a²b ⇒ b⁴

Right Cayley graph (truncated)