Matroid 4.7.42
| Label | 4.7.42 |
|---|---|
| Id | r4_n7_0000000**0*****00**0*****0****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 | yes |
| Quaternary | yes |
| Graphic | no |
Realization space
| Status | computed_realization_space |
|---|---|
| Dimension of realization space | 1 |
| 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": 1,
"free_rank": 1,
"torus_rank": 1,
"core_dim": 0,
"qbar_components": 1,
"type": "rational",
"reason": "free realization space"
}
] |
| Good basis | not computed |
| Good basis v2 | 1,3,4,6 |
Geometry
Other
| Char poly splits | false |
|---|---|
| Simplicial arrangement | no |
| Realization space: n qbar components | 1 |
Tutte polynomial
\(T = x^{4} + x^{3} y + 2 x^{3} + 2 x^{2} y + 3 x^{2} + x y^{2} + 4 x y + 2 x + y^{3} + 3 y^{2} + 2 y\)
Realization space
| Ring | \(\mathbb{Z}[x_{1}]\) |
|---|---|
| Defining ideal | \(\left(0\right)\) |
| Inequations | \(x_{1} - 1 \neq 0\), \(x_{1} \neq 0\) |
| Realization matrix | \(\begin{pmatrix}1 & 1 & 0 & 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 & 1 & 0 & 1 \\ 0 & 0 & 0 & 1 & 1 & 0 & x_{1} \\ 0 & 0 & 0 & 0 & 0 & 1 & 1\end{pmatrix}\) |
Combinatorics
Computed on the fly from the id.
Bases (22)
{1,3,4,6} {2,3,4,6} {1,3,5,6} {2,3,5,6} {1,4,5,6} {2,4,5,6} {3,4,5,6} {1,3,4,7} {2,3,4,7} {1,3,5,7} {2,3,5,7} {1,4,5,7} {2,4,5,7} {3,4,5,7} {1,3,6,7} {2,3,6,7} {1,4,6,7} {2,4,6,7} {1,5,6,7} {2,5,6,7} {3,5,6,7} {4,5,6,7}Non-bases (13)
{1,2,3,4} {1,2,3,5} {1,2,4,5} {1,3,4,5} {2,3,4,5} {1,2,3,6} {1,2,4,6} {1,2,5,6} {1,2,3,7} {1,2,4,7} {1,2,5,7} {1,2,6,7} {3,4,6,7}Circuits (8)
{1,2} {1,3,4,5} {2,3,4,5} {3,4,6,7} {1,3,5,6,7} {2,3,5,6,7} {1,4,5,6,7} {2,4,5,6,7}Flats by rank (37)
- rank 0 (1): {}
- rank 1 (6): {1,2} {3} {4} {5} {6} {7}
- rank 2 (15): {1,2,3} {1,2,4} {3,4} {1,2,5} {3,5} {4,5} {1,2,6} {3,6} {4,6} {5,6} {1,2,7} {3,7} {4,7} {5,7} {6,7}
- rank 3 (14): {1,2,3,4,5} {1,2,3,6} {1,2,4,6} {1,2,5,6} {3,5,6} {4,5,6} {1,2,3,7} {1,2,4,7} {1,2,5,7} {3,5,7} {4,5,7} {1,2,6,7} {3,4,6,7} {5,6,7}
- rank 4 (1): {1,2,3,4,5,6,7}
Hyperplanes (14)
{1,2,3,4,5} {1,2,3,6} {1,2,4,6} {1,2,5,6} {3,5,6} {4,5,6} {1,2,3,7} {1,2,4,7} {1,2,5,7} {3,5,7} {4,5,7} {1,2,6,7} {3,4,6,7} {5,6,7}Dual (rank 3)
Revlex encoding in this labeling (not canonicalized, so not linked): ****0****0*****0**00*****0**0000000
Bases: {2,5,7} {1,5,7} {2,4,7} {1,4,7} {2,3,7} {1,3,7} {1,2,7} {2,5,6} {1,5,6} {2,4,6} {1,4,6} {2,3,6} {1,3,6} {1,2,6} {2,4,5} {1,4,5} {2,3,5} {1,3,5} {2,3,4} {1,3,4} {1,2,4} {1,2,3}
Loops: none. Parallel classes of size > 1: {1,2}.
Downloads
- Record as JSON
- OSCAR:
matroid_from_revlex_basis_encoding("0000000**0*****00**0*****0****0****", 4, 7)