#57 ⟨a, b | aa=a, bb=a⟩
Quick links
- Properties
- Elements
- Staircase diagram
- Cayley table
- Right Cayley graph
- Rewriting system
- Same cardinality
- Isomorphic instances
- Presentation has sum-of-sides 6
- Isomorphic to ℕ(4 = 2)
- Finite commutative monoid with 4 elements
- Not cancellative, because multiplication by a is not injective:
-
a ⋅ a = a and a ⋅ 1 = a, however a ≠ 1
- Commutative Gröbner basis: ⟨a, b | b4=b2, a=b2⟩
- Cancellative quotient is isomorphic to ℤ2
- Enveloping group is isomorphic to ℤ2
- Group of units is isomorphic to ℤ1
- 2 Archimedian components:
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 non-trivial idempotent:
- Order of generators:
- a: index 1, period 1
- b: index 2, period 2
- Histogram:
| index 1, period 1 | 1 element | b2 |
| index 1, period 2 | 1 element | b3 |
| index 2, period 2 | 1 element | b |
Idempotents are shown in bold.
|
1 | b | b2 | b3 |
| 1 | 1 | b | b2 | b3 |
| b | b | b2 | b3 | b2 |
| b2 | b2 | b3 | b2 | b3 |
| b3 | b3 | b2 | b3 | b2 |
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:aa=a,bb=a b/a
bbbb=bb
a=bb
8 unique, 1570 total
| Σ | # | Presentation | Description | Related |
| 5 | 7 | ⟨a, b | aa=b, bb=1⟩ | Isomorphic to ℤ4 | 1419 iso |
| 6 | 61 | ⟨a, b | aa=b, bb=a⟩ | Isomorphic to ℕ(4 = 1) | 72 iso |
| 7 | 158 | ⟨a, b | ab=aa, ba=b⟩ | Finite non-commutative monoid with 4 elements | 8 iso, 6 anti-iso |
| 7 | 159 | ⟨a, b | ab=aa, bb=a⟩ | Isomorphic to ℕ(4 = 3) | 16 iso |
| 7 | 242 | ⟨a, b | aa=a, abb=b⟩ | Finite non-commutative monoid with 4 elements | 14 iso |
| 7 | 280 | ⟨a, b | ab=a, bb=aa⟩ | Finite commutative monoid with 4 elements | 17 iso |
| 9 | 2881 | ⟨a, b | aa=a, abbba=b⟩ | Finite commutative monoid with 4 elements | 8 iso |
| 10 | 5033 | ⟨a, b | aaa=aa, abba=b⟩ | Finite commutative monoid with 4 elements | 2 iso |
The mapping is from the listed presentation's alphabet to the current rewriting system's alphabet.
37 total
| Σ | # | Presentation | Mapping |
| 7 | 250 | ⟨a, b | aa=b, aab=b⟩ | φ(a) = b, φ(b) = bb |
| 7 | 252 | ⟨a, b | aa=b, aba=b⟩ | φ(a) = b, φ(b) = bb |
| 7 | 276 | ⟨a, b | aa=a, bb=aa⟩ | φ(a) = bb, φ(b) = b |
| 7 | 278 | ⟨a, b | aa=b, bb=aa⟩ | φ(a) = b, φ(b) = bb |
| 8 | 631 | ⟨a, b | ab=aa, aaa=b⟩ | φ(a) = b, φ(b) = bbb |
| 8 | 633 | ⟨a, b | ab=aa, aab=b⟩ | φ(a) = b, φ(b) = bbb |
| 8 | 635 | ⟨a, b | ab=aa, aba=b⟩ | φ(a) = b, φ(b) = bbb |
| 8 | 637 | ⟨a, b | ab=aa, abb=b⟩ | φ(a) = b, φ(b) = bbb |
| 8 | 901 | ⟨a, b | aa=b, aaaa=b⟩ | φ(a) = b, φ(b) = bb |
| 8 | 954 | ⟨a, b | aa=a, aaa=bb⟩ | φ(a) = bb, φ(b) = b |
| 8 | 975 | ⟨a, b | aa=b, aab=aa⟩ | φ(a) = b, φ(b) = bb |
| 8 | 979 | ⟨a, b | aa=b, aba=aa⟩ | φ(a) = b, φ(b) = bb |
| 9 | 1611 | ⟨a, b | aab=aa, aba=b⟩ | φ(a) = b, φ(b) = bb |
| 9 | 3002 | ⟨a, b | aa=a, aaaa=bb⟩ | φ(a) = bb, φ(b) = b |
| 9 | 3036 | ⟨a, b | aa=b, aaaa=aa⟩ | φ(a) = b, φ(b) = bb |
| 10 | 5101 | ⟨a, b | aab=aa, aabb=b⟩ | φ(a) = b, φ(b) = bb |
| 10 | 5105 | ⟨a, b | aab=aa, abab=b⟩ | φ(a) = b, φ(b) = bb |
| 10 | 5107 | ⟨a, b | aab=aa, abba=b⟩ | φ(a) = b, φ(b) = bb |
| 10 | 5233 | ⟨a, b | aba=aa, abba=b⟩ | φ(a) = b, φ(b) = bb |
| 10 | 6562 | ⟨a, b | aaa=b, aaaa=aa⟩ | φ(a) = b, φ(b) = bbb |
| 10 | 6613 | ⟨a, b | aab=a, aabb=bb⟩ | φ(a) = bbb, φ(b) = b |
| 10 | 6621 | ⟨a, b | aab=a, abab=bb⟩ | φ(a) = bbb, φ(b) = b |
| 10 | 6625 | ⟨a, b | aab=a, abba=bb⟩ | φ(a) = bbb, φ(b) = b |
| 10 | 6666 | ⟨a, b | aab=b, aaab=aa⟩ | φ(a) = b, φ(b) = bbb |
| 10 | 6765 | ⟨a, b | aba=b, aaab=aa⟩ | φ(a) = b, φ(b) = bbb |
| 10 | 6769 | ⟨a, b | aba=b, aaba=aa⟩ | φ(a) = b, φ(b) = bbb |
| 10 | 8842 | ⟨a, b | aa=a, aaaaa=bb⟩ | φ(a) = bb, φ(b) = b |
| 11 | 15560 | ⟨a, b | aab=aa, aabbb=b⟩ | φ(a) = b, φ(b) = bb |
| 11 | 15568 | ⟨a, b | aab=aa, ababb=b⟩ | φ(a) = b, φ(b) = bb |
| 11 | 15572 | ⟨a, b | aab=aa, abbab=b⟩ | φ(a) = b, φ(b) = bb |
| 11 | 15574 | ⟨a, b | aab=aa, abbba=b⟩ | φ(a) = b, φ(b) = bb |
| 11 | 15826 | ⟨a, b | aba=aa, abbba=b⟩ | φ(a) = b, φ(b) = bb |
| 11 | 19508 | ⟨a, b | aab=b, aaaab=aa⟩ | φ(a) = b, φ(b) = bb |
| 11 | 19707 | ⟨a, b | aba=b, aaaab=aa⟩ | φ(a) = b, φ(b) = bb |
| 11 | 19711 | ⟨a, b | aba=b, aaaba=aa⟩ | φ(a) = b, φ(b) = bb |
| 11 | 19719 | ⟨a, b | aba=b, aabaa=aa⟩ | φ(a) = b, φ(b) = bb |
| 11 | 24590 | ⟨a, b | aa=a, aaaaaa=bb⟩ | φ(a) = bb, φ(b) = b |