〈a, b | aaba=b, abbbb=b〉

Properties

• Infinite commutative monoid
• Isomorphic to commutative presentation: 〈a, b | 4b=2a+b, 3a+b=b〉
• Grothendieck group is ℤ₉

Completion parameters

• Reduction order: left-to-right b/a

Complete rewriting system

1. b¹⁰ ⇒ b
2. ab ⇒ b⁷
3. ba ⇒ b⁷

Right Cayley graph (truncated)