| 1 | a | b | a2 | ba | b2 | a3 | ba2 | b2a | b3 | a4 | ba3 | b2a2 | b3a | ba4 | b2a3 | b3a2 | b2a4 | b3a3 | b3a4 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | a | b | a2 | ba | b2 | a3 | ba2 | b2a | b3 | a4 | ba3 | b2a2 | b3a | ba4 | b2a3 | b3a2 | b2a4 | b3a3 | b3a4 |
| a | a | a2 | a2 | a3 | a3 | a3 | a4 | a4 | a4 | a4 | a | a | a | a | a2 | a2 | a2 | a3 | a3 | a4 |
| b | b | ba | b2 | ba2 | b2a | b3 | ba3 | b2a2 | b3a | 1 | ba4 | b2a3 | b3a2 | a | b2a4 | b3a3 | a2 | b3a4 | a3 | a4 |
| a2 | a2 | a3 | a3 | a4 | a4 | a4 | a | a | a | a | a2 | a2 | a2 | a2 | a3 | a3 | a3 | a4 | a4 | a |
| ba | ba | ba2 | ba2 | ba3 | ba3 | ba3 | ba4 | ba4 | ba4 | ba4 | ba | ba | ba | ba | ba2 | ba2 | ba2 | ba3 | ba3 | ba4 |
| b2 | b2 | b2a | b3 | b2a2 | b3a | 1 | b2a3 | b3a2 | a | b | b2a4 | b3a3 | a2 | ba | b3a4 | a3 | ba2 | a4 | ba3 | ba4 |
| a3 | a3 | a4 | a4 | a | a | a | a2 | a2 | a2 | a2 | a3 | a3 | a3 | a3 | a4 | a4 | a4 | a | a | a2 |
| ba2 | ba2 | ba3 | ba3 | ba4 | ba4 | ba4 | ba | ba | ba | ba | ba2 | ba2 | ba2 | ba2 | ba3 | ba3 | ba3 | ba4 | ba4 | ba |
| b2a | b2a | b2a2 | b2a2 | b2a3 | b2a3 | b2a3 | b2a4 | b2a4 | b2a4 | b2a4 | b2a | b2a | b2a | b2a | b2a2 | b2a2 | b2a2 | b2a3 | b2a3 | b2a4 |
| b3 | b3 | b3a | 1 | b3a2 | a | b | b3a3 | a2 | ba | b2 | b3a4 | a3 | ba2 | b2a | a4 | ba3 | b2a2 | ba4 | b2a3 | b2a4 |
| a4 | a4 | a | a | a2 | a2 | a2 | a3 | a3 | a3 | a3 | a4 | a4 | a4 | a4 | a | a | a | a2 | a2 | a3 |
| ba3 | ba3 | ba4 | ba4 | ba | ba | ba | ba2 | ba2 | ba2 | ba2 | ba3 | ba3 | ba3 | ba3 | ba4 | ba4 | ba4 | ba | ba | ba2 |
| b2a2 | b2a2 | b2a3 | b2a3 | b2a4 | b2a4 | b2a4 | b2a | b2a | b2a | b2a | b2a2 | b2a2 | b2a2 | b2a2 | b2a3 | b2a3 | b2a3 | b2a4 | b2a4 | b2a |
| b3a | b3a | b3a2 | b3a2 | b3a3 | b3a3 | b3a3 | b3a4 | b3a4 | b3a4 | b3a4 | b3a | b3a | b3a | b3a | b3a2 | b3a2 | b3a2 | b3a3 | b3a3 | b3a4 |
| ba4 | ba4 | ba | ba | ba2 | ba2 | ba2 | ba3 | ba3 | ba3 | ba3 | ba4 | ba4 | ba4 | ba4 | ba | ba | ba | ba2 | ba2 | ba3 |
| b2a3 | b2a3 | b2a4 | b2a4 | b2a | b2a | b2a | b2a2 | b2a2 | b2a2 | b2a2 | b2a3 | b2a3 | b2a3 | b2a3 | b2a4 | b2a4 | b2a4 | b2a | b2a | b2a2 |
| b3a2 | b3a2 | b3a3 | b3a3 | b3a4 | b3a4 | b3a4 | b3a | b3a | b3a | b3a | b3a2 | b3a2 | b3a2 | b3a2 | b3a3 | b3a3 | b3a3 | b3a4 | b3a4 | b3a |
| b2a4 | b2a4 | b2a | b2a | b2a2 | b2a2 | b2a2 | b2a3 | b2a3 | b2a3 | b2a3 | b2a4 | b2a4 | b2a4 | b2a4 | b2a | b2a | b2a | b2a2 | b2a2 | b2a3 |
| b3a3 | b3a3 | b3a4 | b3a4 | b3a | b3a | b3a | b3a2 | b3a2 | b3a2 | b3a2 | b3a3 | b3a3 | b3a3 | b3a3 | b3a4 | b3a4 | b3a4 | b3a | b3a | b3a2 |
| b3a4 | b3a4 | b3a | b3a | b3a2 | b3a2 | b3a2 | b3a3 | b3a3 | b3a3 | b3a3 | b3a4 | b3a4 | b3a4 | b3a4 | b3a | b3a | b3a | b3a2 | b3a2 | b3a3 |
| Length: | Presentation: | Description: | Related: |
|---|---|---|---|
| 8 | 〈a, b | aab=a, bbbb=1〉 | Finite non-commutative monoid with 20 elements | 3 isomorphic, 1 anti-isomorphic |
| 9 | 〈a, b | abab=a, bbbb=1〉 | Finite non-commutative monoid with 20 elements | 2 isomorphic |
| 9 | 〈a, b | aba=ab, bbbb=1〉 | Finite non-commutative monoid with 20 elements | 1 isomorphic, 1 anti-isomorphic |
| 9 | 〈a, b | ab=aa, bbbb=b〉 | Finite non-commutative monoid with 20 elements | |
| 10 | 〈a, b | abb=aab, aaaa=1〉 | Finite non-commutative monoid with 20 elements | 2 isomorphic |
| 10 | 〈a, b | baa=abb, abab=1〉 | Finite non-Abelian group with 20 elements | 1 isomorphic, 1 anti-isomorphic |
| 10 | 〈a, b | aaaaa=1, abbbb=1〉 | Isomorphic to ℤ20 | 16 isomorphic |
| 10 | 〈a, b | aab=bb, aaaa=a〉 | Finite non-commutative monoid with 20 elements | |
| 10 | 〈a, b | aaa=bb, bab=aa〉 | Finite non-commutative monoid with 20 elements | 1 isomorphic |
| 10 | 〈a, b | aba=a, aaaa=bb〉 | Finite non-commutative monoid with 20 elements | |
| 10 | 〈a, b | aba=b, aaaa=bb〉 | Finite non-commutative monoid with 20 elements | |
| 10 | 〈a, b | ab=aa, bbbb=bb〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aaaa=aa, abbb=b〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aaab=bb, bbba=a〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aaaa=a, bbbbb=a〉 | Finite commutative monoid with 20 elements | |
| 11 | 〈a, b | aaaa=b, bbbbb=a〉 | Finite commutative monoid with 20 elements | |
| 11 | 〈a, b | aaaa=b, bbbbb=b〉 | Finite commutative monoid with 20 elements | |
| 11 | 〈a, b | aab=ba, abbabb=1〉 | Finite non-Abelian group with 20 elements | 2 isomorphic |
| 11 | 〈a, b | aba=bb, baaab=a〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aab=aa, baba=bb〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aba=aa, aaaa=bb〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aba=aa, aaab=bb〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aba=bb, abb=aaa〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | aaaa=1, aaabab=b〉 | Finite non-commutative monoid with 20 elements | 1 isomorphic |
| 11 | 〈a, b | aaaa=1, aabab=ab〉 | Finite non-commutative monoid with 20 elements | 1 isomorphic |
| 11 | 〈a, b | aba=b, aaaaabb=1〉 | Finite non-Abelian group with 20 elements | 3 isomorphic |
| 11 | 〈a, b | aab=a, bbbbb=bb〉 | Finite non-commutative monoid with 20 elements | |
| 11 | 〈a, b | ab=aa, bbbb=bbb〉 | Finite non-commutative monoid with 20 elements |
| Length: | Presentation: |
|---|---|
| 10 | 〈a, b | abb=aba, aaaa=1〉 |