| 1 | a | b | ab | ba | b2 | aba | ab2 | b2a | b3 | ab2a | ab3 | b4 | ab4 | b5 | ab5 | b6 | ab6 | b7 | b8 | b9 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | a | b | ab | ba | b2 | aba | ab2 | b2a | b3 | ab2a | ab3 | b4 | ab4 | b5 | ab5 | b6 | ab6 | b7 | b8 | b9 |
| a | a | b3 | ab | b4 | aba | ab2 | ab5 | b5 | ab2a | ab3 | ab4 | b6 | ab4 | b7 | ab5 | b8 | ab6 | b9 | ab4 | ab5 | ab6 |
| b | b | ba | b2 | ab3 | b2a | b3 | b6 | ab4 | ab3 | b4 | b8 | ab5 | b5 | ab6 | b6 | ab4 | b7 | ab5 | b8 | b9 | b7 |
| ab | ab | aba | ab2 | b6 | ab2a | ab3 | ab6 | b7 | b6 | ab4 | ab5 | b8 | ab5 | b9 | ab6 | b7 | ab4 | b8 | ab5 | ab6 | ab4 |
| ba | ba | b4 | ab3 | b5 | b6 | ab4 | ab4 | b6 | b8 | ab5 | ab6 | b7 | ab6 | b8 | ab4 | b9 | ab5 | b7 | ab6 | ab4 | ab5 |
| b2 | b2 | b2a | b3 | ab5 | ab3 | b4 | b7 | ab6 | ab5 | b5 | b9 | ab4 | b6 | ab5 | b7 | ab6 | b8 | ab4 | b9 | b7 | b8 |
| aba | aba | ab4 | b6 | ab5 | ab6 | b7 | b7 | ab6 | ab5 | b8 | b9 | ab4 | b9 | ab5 | b7 | ab6 | b8 | ab4 | b9 | b7 | b8 |
| ab2 | ab2 | ab2a | ab3 | b8 | b6 | ab4 | ab4 | b9 | b8 | ab5 | ab6 | b7 | ab6 | b8 | ab4 | b9 | ab5 | b7 | ab6 | ab4 | ab5 |
| b2a | b2a | b5 | ab5 | b6 | b7 | ab6 | ab6 | b7 | b9 | ab4 | ab5 | b8 | ab5 | b9 | ab6 | b7 | ab4 | b8 | ab5 | ab6 | ab4 |
| b3 | b3 | ab3 | b4 | ab4 | ab5 | b5 | b8 | ab5 | ab4 | b6 | b7 | ab6 | b7 | ab4 | b8 | ab5 | b9 | ab6 | b7 | b8 | b9 |
| ab2a | ab2a | ab5 | b8 | ab6 | ab4 | b9 | b9 | ab4 | ab6 | b7 | b8 | ab5 | b8 | ab6 | b9 | ab4 | b7 | ab5 | b8 | b9 | b7 |
| ab3 | ab3 | b6 | ab4 | b7 | b8 | ab5 | ab5 | b8 | b7 | ab6 | ab4 | b9 | ab4 | b7 | ab5 | b8 | ab6 | b9 | ab4 | ab5 | ab6 |
| b4 | b4 | ab5 | b5 | ab6 | ab4 | b6 | b9 | ab4 | ab6 | b7 | b8 | ab5 | b8 | ab6 | b9 | ab4 | b7 | ab5 | b8 | b9 | b7 |
| ab4 | ab4 | b8 | ab5 | b9 | b7 | ab6 | ab6 | b7 | b9 | ab4 | ab5 | b8 | ab5 | b9 | ab6 | b7 | ab4 | b8 | ab5 | ab6 | ab4 |
| b5 | b5 | ab4 | b6 | ab5 | ab6 | b7 | b7 | ab6 | ab5 | b8 | b9 | ab4 | b9 | ab5 | b7 | ab6 | b8 | ab4 | b9 | b7 | b8 |
| ab5 | ab5 | b7 | ab6 | b8 | b9 | ab4 | ab4 | b9 | b8 | ab5 | ab6 | b7 | ab6 | b8 | ab4 | b9 | ab5 | b7 | ab6 | ab4 | ab5 |
| b6 | b6 | ab6 | b7 | ab4 | ab5 | b8 | b8 | ab5 | ab4 | b9 | b7 | ab6 | b7 | ab4 | b8 | ab5 | b9 | ab6 | b7 | b8 | b9 |
| ab6 | ab6 | b9 | ab4 | b7 | b8 | ab5 | ab5 | b8 | b7 | ab6 | ab4 | b9 | ab4 | b7 | ab5 | b8 | ab6 | b9 | ab4 | ab5 | ab6 |
| b7 | b7 | ab5 | b8 | ab6 | ab4 | b9 | b9 | ab4 | ab6 | b7 | b8 | ab5 | b8 | ab6 | b9 | ab4 | b7 | ab5 | b8 | b9 | b7 |
| b8 | b8 | ab4 | b9 | ab5 | ab6 | b7 | b7 | ab6 | ab5 | b8 | b9 | ab4 | b9 | ab5 | b7 | ab6 | b8 | ab4 | b9 | b7 | b8 |
| b9 | b9 | ab6 | b7 | ab4 | ab5 | b8 | b8 | ab5 | ab4 | b9 | b7 | ab6 | b7 | ab4 | b8 | ab5 | b9 | ab6 | b7 | b8 | b9 |
| Length: | Presentation: | Description: | Related: |
|---|---|---|---|
| 8 | 〈a, b | aaa=ab, bbb=1〉 | Finite non-commutative monoid with 21 elements | 6 isomorphic, 9 anti-isomorphic |
| 8 | 〈a, b | aaa=1, abbb=b〉 | Finite non-commutative monoid with 21 elements | 10 isomorphic, 5 anti-isomorphic |
| 9 | 〈a, b | aaa=ab, bbb=b〉 | Finite non-commutative monoid with 21 elements | 1 anti-isomorphic |
| 9 | 〈a, b | aaa=1, babb=ab〉 | Finite non-commutative monoid with 21 elements | 6 isomorphic |
| 10 | 〈a, b | aaa=aa, bbb=ab〉 | Finite non-commutative monoid with 21 elements | |
| 10 | 〈a, b | aaa=a, abbbb=b〉 | Finite non-commutative monoid with 21 elements | |
| 11 | 〈a, b | aaaaa=b, abbbb=1〉 | Isomorphic to ℤ21 | 13 isomorphic |
| 11 | 〈a, b | bab=aaa, abba=b〉 | Finite non-commutative monoid with 21 elements | |
| 11 | 〈a, b | aab=ba, ababab=1〉 | Finite non-Abelian group with 21 elements | 1 isomorphic |
| 11 | 〈a, b | aaa=a, ababbb=b〉 | Finite non-commutative monoid with 21 elements | 1 isomorphic |
| 11 | 〈a, b | aba=b, baaaab=a〉 | Finite non-commutative monoid with 21 elements | |
| 11 | 〈a, b | aaa=1, abbab=aba〉 | Finite non-commutative monoid with 21 elements |