#12159 ⟨a, b | aaaa=aa, abbb=b⟩
Contents
- Properties
- Finite structure
- Cayley table
- Right Cayley graph
- Left Cayley graph
- Rewriting system
- Same cardinality
- Sum of relation sides is 11
- Finite non-commutative monoid with 20 elements
- Not cancellative, because multiplication by b is not injective:
-
b ⋅ b4 = b and b ⋅ 1 = b, however b4 ≠ 1
Elements in the center commute with all other elements.
An idempotent element x satisfies x2 = x.
The index and period of x is the least m (index) and n (period) such that x(m+n) = xm.
- 1 element center:
- 5 non-trivial idempotents:
- Order of generators:
- a: index 2, period 2
- b: index 1, period 4
- Histogram:
| index 1, period 1 | 5 elements | a2, b2a, b4, b2a3, b4a2 |
| index 1, period 2 | 5 elements | b2, a3, b2a2, b4a, b4a3 |
| index 1, period 4 | 8 elements | b, ba, ba2, b3, ba3, ... |
| index 2, period 2 | 1 element | a |
Idempotents are shown in bold.
|
1 | a | b | a2 | ba | b2 | a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b3a3 | b4a2 | b4a3 |
| 1 | 1 | a | b | a2 | ba | b2 | a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b3a3 | b4a2 | b4a3 |
| a | a | a2 | b3 | a3 | b3a | b4 | a2 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | ba3 | b2a2 | b2a3 |
| b | b | ba | b2 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b4a3 | ba2 | ba3 |
| a2 | a2 | a3 | b | a2 | ba | b2 | a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b3a3 | b4a2 | b4a3 |
| ba | ba | ba2 | b4 | ba3 | b4a | b | ba2 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b2a3 | b3a2 | b3a3 |
| b2 | b2 | b2a | b3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | ba3 | b2a2 | b2a3 |
| a3 | a3 | a2 | b3 | a3 | b3a | b4 | a2 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | ba3 | b2a2 | b2a3 |
| ba2 | ba2 | ba3 | b2 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b4a3 | ba2 | ba3 |
| b2a | b2a | b2a2 | b | b2a3 | ba | b2 | b2a2 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b3a3 | b4a2 | b4a3 |
| b3 | b3 | b3a | b4 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b2a3 | b3a2 | b3a3 |
| ba3 | ba3 | ba2 | b4 | ba3 | b4a | b | ba2 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b2a3 | b3a2 | b3a3 |
| b2a2 | b2a2 | b2a3 | b3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | ba3 | b2a2 | b2a3 |
| b3a | b3a | b3a2 | b2 | b3a3 | b2a | b3 | b3a2 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b4a3 | ba2 | ba3 |
| b4 | b4 | b4a | b | b4a2 | ba | b2 | b4a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b3a3 | b4a2 | b4a3 |
| b2a3 | b2a3 | b2a2 | b | b2a3 | ba | b2 | b2a2 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b3a3 | b4a2 | b4a3 |
| b3a2 | b3a2 | b3a3 | b4 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b2a3 | b3a2 | b3a3 |
| b4a | b4a | b4a2 | b3 | b4a3 | b3a | b4 | b4a2 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | ba3 | b2a2 | b2a3 |
| b3a3 | b3a3 | b3a2 | b2 | b3a3 | b2a | b3 | b3a2 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b4a3 | ba2 | ba3 |
| b4a2 | b4a2 | b4a3 | b | b4a2 | ba | b2 | b4a3 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | b4 | b2a3 | b3a2 | b4a | b3a3 | b4a2 | b4a3 |
| b4a3 | b4a3 | b4a2 | b3 | b4a3 | b3a | b4 | b4a2 | b3a2 | b4a | b | b3a3 | b4a2 | ba | b2 | b4a3 | ba2 | b2a | ba3 | b2a2 | b2a3 |
Idempotents are shown in bold.
Idempotents are shown in bold.
- Reduction order:
- Left-to-right recursive path with deg(b) = 0; deg(a) = 1
- Certificate: derivations of all rewriting rules from the defining relations.
# ab:aaaa=aa,abbb=b b/a - -
bbbbb=b
ab=bbb
aaaa=aa
20 unique, 65 total
| Σ | # | Presentation | Properties | Description | φ |
| 8 | 526 | ⟨a, b | aab=a, bbbb=1⟩ | Noc 20 | | 19 |
| 9 | 2207 | ⟨a, b | ab=aa, bbbb=b⟩ | Noc 20 | | 1 |
| 10 | 4095 | ⟨a, b | baa=abb, abab=1⟩ | Grp 20 | | 5 |
| 10 | 4212 | ⟨a, b | aaaaa=1, abbbb=1⟩ | Grp Com 20 | ℤ20 | 16 |
| 10 | 5349 | ⟨a, b | aaa=bb, bab=aa⟩ | Noc 20 | | 1 |
| 10 | 6728 | ⟨a, b | aba=a, aaaa=bb⟩ | Noc 20 | | |
| 10 | 6764 | ⟨a, b | aba=b, aaaa=bb⟩ | Noc 20 | | |
| 10 | 7117 | ⟨a, b | ab=aa, bbbb=bb⟩ | Noc 20 | | |
| 11 | 12322 | ⟨a, b | aaab=bb, bbba=a⟩ | Noc 20 | | |
| 11 | 14367 | ⟨a, b | aaaa=a, bbbbb=a⟩ | Noc Com 20 | ℕ(20 = 5) | |
| 11 | 14407 | ⟨a, b | aaaa=b, bbbbb=a⟩ | Noc Com 20 | ℕ(20 = 1) | |
| 11 | 14408 | ⟨a, b | aaaa=b, bbbbb=b⟩ | Noc Com 20 | ℕ(20 = 4) | |
| 11 | 15933 | ⟨a, b | aba=bb, baaab=a⟩ | Noc 20 | | |
| 11 | 16124 | ⟨a, b | aab=aa, baba=bb⟩ | Noc 20 | | |
| 11 | 16339 | ⟨a, b | aba=aa, aaaa=bb⟩ | Noc 20 | | |
| 11 | 16343 | ⟨a, b | aba=aa, aaab=bb⟩ | Noc 20 | | |
| 11 | 16545 | ⟨a, b | aba=bb, abb=aaa⟩ | Noc 20 | | |
| 11 | 18619 | ⟨a, b | aba=b, aaaaabb=1⟩ | Grp 20 | | 3 |
| 11 | 19503 | ⟨a, b | aab=a, bbbbb=bb⟩ | Noc 20 | | |
| 11 | 21047 | ⟨a, b | ab=aa, bbbb=bbb⟩ | Noc 20 | | |