\begin{equation} \DeclareMathOperator\Gr{Gr} \DeclareMathOperator\LGr{LGr} \DeclareMathOperator\OGr{OGr} \DeclareMathOperator\SGr{SGr} \DeclareMathOperator\Kzero{K_0} \DeclareMathOperator\index{i} \DeclareMathOperator\rk{rk} \end{equation}

Grassmannian.info

A periodic table of (generalised) Grassmannians.

Orthogonal Grassmannian $\OGr(2,13)$

Betti numbers
\begin{align*} \mathrm{b}_{ 1 } &= 1 \\ \mathrm{b}_{ 2 } &= 1 \\ \mathrm{b}_{ 3 } &= 2 \\ \mathrm{b}_{ 4 } &= 2 \\ \mathrm{b}_{ 5 } &= 3 \\ \mathrm{b}_{ 6 } &= 3 \\ \mathrm{b}_{ 7 } &= 4 \\ \mathrm{b}_{ 8 } &= 4 \\ \mathrm{b}_{ 9 } &= 5 \\ \mathrm{b}_{ 10 } &= 5 \\ \mathrm{b}_{ 11 } &= 5 \\ \mathrm{b}_{ 12 } &= 5 \\ \mathrm{b}_{ 13 } &= 4 \\ \mathrm{b}_{ 14 } &= 4 \\ \mathrm{b}_{ 15 } &= 3 \\ \mathrm{b}_{ 16 } &= 3 \\ \mathrm{b}_{ 17 } &= 2 \\ \mathrm{b}_{ 18 } &= 2 \\ \mathrm{b}_{ 19 } &= 1 \\ \mathrm{b}_{ 20 } &= 1 \end{align*}
Basic information
dimension
19
index
10
Euler characteristic
60
Betti numbers
$\mathrm{b}_{ 1 } = 1$, $\mathrm{b}_{ 2 } = 1$, $\mathrm{b}_{ 3 } = 2$, $\mathrm{b}_{ 4 } = 2$, $\mathrm{b}_{ 5 } = 3$, $\mathrm{b}_{ 6 } = 3$, $\mathrm{b}_{ 7 } = 4$, $\mathrm{b}_{ 8 } = 4$, $\mathrm{b}_{ 9 } = 5$, $\mathrm{b}_{ 10 } = 5$, $\mathrm{b}_{ 11 } = 5$, $\mathrm{b}_{ 12 } = 5$, $\mathrm{b}_{ 13 } = 4$, $\mathrm{b}_{ 14 } = 4$, $\mathrm{b}_{ 15 } = 3$, $\mathrm{b}_{ 16 } = 3$, $\mathrm{b}_{ 17 } = 2$, $\mathrm{b}_{ 18 } = 2$, $\mathrm{b}_{ 19 } = 1$, $\mathrm{b}_{ 20 } = 1$
$\mathrm{Aut}^0(\OGr(2,13))$
$\mathrm{SO}_{ 13 }$
$\pi_0\mathrm{Aut}(\OGr(2,13))$
$1$
$\dim\mathrm{Aut}^0(\OGr(2,13))$
78
Projective geometry
minimal embedding

$\OGr(2,13)\hookrightarrow\mathbb{P}^{ 77 }$

degree
67184
Hilbert series
1, 78, 2275, 37400, 415701, 3461458, 23046023, 128271000, 616258500, 2617486872, 10011037452, 34981096384, 112977874100, 340467258600, 964904283772, 2588633683064, 6610679343345, 16146190238750, 37871772241875, 85609271147400, ...
Exceptional collections
  • Kuznetsov constructed a full exceptional sequence in 2008, see MR2434094.