Matroid 4.7.28
| Label | 4.7.28 |
|---|---|
| Id | r4_n7_000000*********0******************* |
| Rank | 4 |
| n | 7 |
Basic invariants
Representability
| Characteristic set | characteristic 0 and all primes [0] |
|---|---|
| Realizable | yes |
| Realizable char0 | yes |
| Regular | no |
| Binary | no |
| Ternary | no |
| Quaternary | no |
| Graphic | no |
Realization space
| Status | computed_realization_space |
|---|---|
| Dimension of realization space | 3 |
| Expected dimension over ℤ | not computed |
| Components of realization space | 1 |
| Free realization space | yes |
| Principal ideal | yes |
| Birational type | rational how determined: birational type method: free_presentation |
| Birational type components | show[
{
"dim": 3,
"free_rank": 3,
"torus_rank": 3,
"core_dim": 0,
"qbar_components": 1,
"type": "rational",
"reason": "free realization space"
}
] |
| Good basis | not computed |
| Good basis v2 | 1,2,4,6 |
Geometry
Other
| Char poly splits | false |
|---|---|
| Simplicial arrangement | no |
| Realization space: n qbar components | 1 |
Tutte polynomial
\(T = x^{4} + 3 x^{3} + x^{2} y + 5 x^{2} + x y^{2} + 3 x y + 5 x + y^{3} + 3 y^{2} + 5 y\)
Realization space
| Ring | \(\mathbb{Z}[x_{1}, x_{2}, x_{3}]\) |
|---|---|
| Defining ideal | \(\left(0\right)\) |
| Inequations | \(x_{1} x_{3} - x_{2} \neq 0\), \(x_{3} - 1 \neq 0\), \(x_{1} x_{3} - x_{2} - x_{3} + 1 \neq 0\), \(x_{1} - x_{2} \neq 0\), \(x_{2} \neq 0\), \(x_{2} - 1 \neq 0\), \(x_{3} \neq 0\), \(x_{1} \neq 0\), \(x_{1} - 1 \neq 0\) |
| Realization matrix | \(\begin{pmatrix}1 & 0 & 1 & 0 & 1 & 0 & 1 \\ 0 & 1 & 1 & 0 & x_{1} & 0 & x_{2} \\ 0 & 0 & 0 & 1 & 1 & 0 & x_{3} \\ 0 & 0 & 0 & 0 & 0 & 1 & 1\end{pmatrix}\) |
Combinatorics
Computed on the fly from the id.
Bases (28)
{1,2,4,6} {1,3,4,6} {2,3,4,6} {1,2,5,6} {1,3,5,6} {2,3,5,6} {1,4,5,6} {2,4,5,6} {3,4,5,6} {1,2,4,7} {1,3,4,7} {2,3,4,7} {1,2,5,7} {1,3,5,7} {2,3,5,7} {1,4,5,7} {2,4,5,7} {3,4,5,7} {1,2,6,7} {1,3,6,7} {2,3,6,7} {1,4,6,7} {2,4,6,7} {3,4,6,7} {1,5,6,7} {2,5,6,7} {3,5,6,7} {4,5,6,7}Non-bases (7)
{1,2,3,4} {1,2,3,5} {1,2,4,5} {1,3,4,5} {2,3,4,5} {1,2,3,6} {1,2,3,7}Circuits (13)
{1,2,3} {1,2,4,5} {1,3,4,5} {2,3,4,5} {1,2,4,6,7} {1,3,4,6,7} {2,3,4,6,7} {1,2,5,6,7} {1,3,5,6,7} {2,3,5,6,7} {1,4,5,6,7} {2,4,5,6,7} {3,4,5,6,7}Flats by rank (50)
- rank 0 (1): {}
- rank 1 (7): {1} {2} {3} {4} {5} {6} {7}
- rank 2 (19): {1,2,3} {1,4} {2,4} {3,4} {1,5} {2,5} {3,5} {4,5} {1,6} {2,6} {3,6} {4,6} {5,6} {1,7} {2,7} {3,7} {4,7} {5,7} {6,7}
- rank 3 (22): {1,2,3,4,5} {1,2,3,6} {1,4,6} {2,4,6} {3,4,6} {1,5,6} {2,5,6} {3,5,6} {4,5,6} {1,2,3,7} {1,4,7} {2,4,7} {3,4,7} {1,5,7} {2,5,7} {3,5,7} {4,5,7} {1,6,7} {2,6,7} {3,6,7} {4,6,7} {5,6,7}
- rank 4 (1): {1,2,3,4,5,6,7}
Hyperplanes (22)
{1,2,3,4,5} {1,2,3,6} {1,4,6} {2,4,6} {3,4,6} {1,5,6} {2,5,6} {3,5,6} {4,5,6} {1,2,3,7} {1,4,7} {2,4,7} {3,4,7} {1,5,7} {2,5,7} {3,5,7} {4,5,7} {1,6,7} {2,6,7} {3,6,7} {4,6,7} {5,6,7}Dual (rank 3)
Revlex encoding in this labeling (not canonicalized, so not linked): *******************0*********000000
Bases: {3,5,7} {2,5,7} {1,5,7} {3,4,7} {2,4,7} {1,4,7} {2,3,7} {1,3,7} {1,2,7} {3,5,6} {2,5,6} {1,5,6} {3,4,6} {2,4,6} {1,4,6} {2,3,6} {1,3,6} {1,2,6} {3,4,5} {2,4,5} {1,4,5} {2,3,5} {1,3,5} {1,2,5} {2,3,4} {1,3,4} {1,2,4} {1,2,3}
Loops: none. Parallel classes of size > 1: none.
Downloads
- Record as JSON
- OSCAR:
matroid_from_revlex_basis_encoding("000000*********0*******************", 4, 7)