[6, 5790] finitely based
[6, 5790] is a commutative semigroup with 2 idempotents and a zero, 1. It is finitely based: 3 identities define its variety, which 11 other semigroups of order six also generate.
Cayley table
| · | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 2 | 1 | 1 | 1 | 1 | 1 | 1 |
| 3 | 1 | 1 | 1 | 1 | 1 | 2 |
| 4 | 1 | 1 | 1 | 4 | 5 | 4 |
| 5 | 1 | 1 | 1 | 5 | 4 | 5 |
| 6 | 1 | 1 | 2 | 4 | 5 | 4 |
The product of the row element and the column element, numbered as in Smallsemi. Blue: idempotents on the diagonal; grey: the zero.
Structure
- Smallsemi
- SmallSemigroup(6, 5790)
- Idempotents
- 1, 4
- Zero
- 1
- Identity
- none
- Nilpotent
- no
- Commutative
- yes
- Regular
- no
- Group
- no
- 𝒥-classes
- 5
- Rank
- 3, generated by {3, 5, 6}
- Self-dual
- yes: anti-isomorphic to itself
Identity basis
Shortest known basis: 3 identities irredundant
- x² ≈ x⁴
- xy ≈ yx
- x³yz ≈ xyz
Irredundant: none of these identities follows from the others; for each, a semigroup satisfies the others but not it. Obtained from a basis certified in Lean by removing identities that follow from the others, with the prover Vampire; the equivalence rests on Vampire's proofs, not on Lean. Shortest known, not known to be minimal.
Basis certified in Lean: 4 identities
- x² ≈ x⁴
- xy ≈ yx
- x²y ≈ x²y³
- x³yz ≈ xyz
Lean proof
Endpoint theorem: SemigroupBasis.Generated.Order6GenericCASRootWrappers.S6_5790.opposite_basis
BasisFor Generated.Order6GenericCASRootWrappers.S6_5790.table.semigroup.opposite Generated.Order6GenericCASRootData.S6_1250.basis
- Table
- The theorem is about the semigroup with exactly this table.
- Method
- other generated proof. A machine-generated proof that builds on semigroups certified earlier: an adapter or wrapper of a transfer found by the campaign's search.
- Size
- Checking this class alone compiles 34 Lean files with 14,877 lines: the endpoint theorem and everything it imports, the shared library included. Of these, 2,755 lines are used by the proof of this class and of no other.
- Census
- SemiBase.Census.S6_5790 checks that the theorem is about the table of this class and concludes Classified; SemiBase.Catalogue.Order6.S6_5790 is the table, with the elements numbered 0 to 5.
Variety
[6, 5790] generates the variety V[1250]; 11 other semigroups of order six generate it too, and 555 semigroups of order six lie in it. [6, 5790] lies in 79 of the 505 varieties of the census, those whose basis it satisfies.
- Directly above
- Directly below
V[1250] in the inclusion graph, with the varieties above and below it.