#6795 ⟨a, b | aba=b, bbbb=aa⟩
Contents
- Properties
- Finite structure
- Cayley table
- Right Cayley graph
- Left Cayley graph
- Rewriting system
- Same cardinality
- Sum of relation sides is 10
- Finite non-commutative monoid with 18 elements
- Not cancellative, because multiplication by b is not injective:
-
b ⋅ b8 = b and b ⋅ 1 = b, however b8 ≠ 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.
- 5 element center:
- 1 non-trivial idempotent:
- Order of generators:
- a: index 2, period 4
- b: index 1, period 8
- Histogram:
| index 1, period 1 | 1 element | b8 |
| index 1, period 2 | 3 elements | ab2, b4, ab6 |
| index 1, period 4 | 4 elements | b2, ab4, b6, ab8 |
| index 1, period 8 | 8 elements | b, ab, b3, ab3, b5, ... |
| index 2, period 4 | 1 element | a |
Idempotents are shown in bold.
|
1 | a | b | ab | b2 | ab2 | b3 | ab3 | b4 | ab4 | b5 | ab5 | b6 | ab6 | b7 | ab7 | b8 | ab8 |
| 1 | 1 | a | b | ab | b2 | ab2 | b3 | ab3 | b4 | ab4 | b5 | ab5 | b6 | ab6 | b7 | ab7 | b8 | ab8 |
| a | a | b4 | ab | b5 | ab2 | b6 | ab3 | b7 | ab4 | b8 | ab5 | b | ab6 | b2 | ab7 | b3 | ab8 | b4 |
| b | b | ab5 | b2 | ab6 | b3 | ab7 | b4 | ab8 | b5 | ab | b6 | ab2 | b7 | ab3 | b8 | ab4 | b | ab5 |
| ab | ab | b | ab2 | b2 | ab3 | b3 | ab4 | b4 | ab5 | b5 | ab6 | b6 | ab7 | b7 | ab8 | b8 | ab | b |
| b2 | b2 | ab2 | b3 | ab3 | b4 | ab4 | b5 | ab5 | b6 | ab6 | b7 | ab7 | b8 | ab8 | b | ab | b2 | ab2 |
| ab2 | ab2 | b6 | ab3 | b7 | ab4 | b8 | ab5 | b | ab6 | b2 | ab7 | b3 | ab8 | b4 | ab | b5 | ab2 | b6 |
| b3 | b3 | ab7 | b4 | ab8 | b5 | ab | b6 | ab2 | b7 | ab3 | b8 | ab4 | b | ab5 | b2 | ab6 | b3 | ab7 |
| ab3 | ab3 | b3 | ab4 | b4 | ab5 | b5 | ab6 | b6 | ab7 | b7 | ab8 | b8 | ab | b | ab2 | b2 | ab3 | b3 |
| b4 | b4 | ab4 | b5 | ab5 | b6 | ab6 | b7 | ab7 | b8 | ab8 | b | ab | b2 | ab2 | b3 | ab3 | b4 | ab4 |
| ab4 | ab4 | b8 | ab5 | b | ab6 | b2 | ab7 | b3 | ab8 | b4 | ab | b5 | ab2 | b6 | ab3 | b7 | ab4 | b8 |
| b5 | b5 | ab | b6 | ab2 | b7 | ab3 | b8 | ab4 | b | ab5 | b2 | ab6 | b3 | ab7 | b4 | ab8 | b5 | ab |
| ab5 | ab5 | b5 | ab6 | b6 | ab7 | b7 | ab8 | b8 | ab | b | ab2 | b2 | ab3 | b3 | ab4 | b4 | ab5 | b5 |
| b6 | b6 | ab6 | b7 | ab7 | b8 | ab8 | b | ab | b2 | ab2 | b3 | ab3 | b4 | ab4 | b5 | ab5 | b6 | ab6 |
| ab6 | ab6 | b2 | ab7 | b3 | ab8 | b4 | ab | b5 | ab2 | b6 | ab3 | b7 | ab4 | b8 | ab5 | b | ab6 | b2 |
| b7 | b7 | ab3 | b8 | ab4 | b | ab5 | b2 | ab6 | b3 | ab7 | b4 | ab8 | b5 | ab | b6 | ab2 | b7 | ab3 |
| ab7 | ab7 | b7 | ab8 | b8 | ab | b | ab2 | b2 | ab3 | b3 | ab4 | b4 | ab5 | b5 | ab6 | b6 | ab7 | b7 |
| b8 | b8 | ab8 | b | ab | b2 | ab2 | b3 | ab3 | b4 | ab4 | b5 | ab5 | b6 | ab6 | b7 | ab7 | b8 | ab8 |
| ab8 | ab8 | b4 | ab | b5 | ab2 | b6 | ab3 | b7 | ab4 | b8 | ab5 | b | ab6 | b2 | ab7 | b3 | ab8 | b4 |
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:aba=b,bbbb=aa b/a - -
bbbbbbbbb=b
ba=abbbbb
aa=bbbb
17 unique, 104 total
| Σ | # | Presentation | Properties | Description | φ |
| 8 | 1121 | ⟨a, b | aa=1, abbba=b⟩ | Noc 18 | | 17 |
| 9 | 3387 | ⟨a, b | aa=1, abbbbb=b⟩ | Noc 18 | | 31 |
| 10 | 5521 | ⟨a, b | aaab=1, bbbbbb=1⟩ | Grp Com 18 | ℤ18 | 33 |
| 10 | 6732 | ⟨a, b | aba=a, aaab=bb⟩ | Noc 18 | | |
| 10 | 6788 | ⟨a, b | aba=b, baab=aa⟩ | Noc 18 | | |
| 10 | 7039 | ⟨a, b | bb=aa, aaaba=b⟩ | Noc 18 | | 2 |
| 10 | 8910 | ⟨a, b | aa=a, bbbbb=ab⟩ | Noc 18 | | 1 |
| 11 | 12187 | ⟨a, b | aaaa=ab, babb=b⟩ | Noc 18 | | 2 |
| 11 | 15797 | ⟨a, b | aab=bb, bbbba=a⟩ | Noc 18 | | |
| 11 | 16042 | ⟨a, b | aaa=ab, bbbb=ab⟩ | Noc 18 | | |
| 11 | 16043 | ⟨a, b | aaa=ab, bbbb=ba⟩ | Noc 18 | | |
| 11 | 16313 | ⟨a, b | aab=bb, baba=aa⟩ | Noc 18 | | |
| 11 | 18758 | ⟨a, b | aaa=a, bbbbbb=a⟩ | Noc Com 18 | ℕ(18 = 6) | |
| 11 | 18830 | ⟨a, b | aaa=b, bbbbbb=a⟩ | Noc Com 18 | ℕ(18 = 1) | |
| 11 | 18831 | ⟨a, b | aaa=b, bbbbbb=b⟩ | Noc Com 18 | ℕ(18 = 3) | |
| 11 | 19624 | ⟨a, b | aab=b, bbbba=aa⟩ | Noc 18 | | |
| 11 | 20914 | ⟨a, b | bb=aa, ababa=aa⟩ | Noc 18 | | 1 |