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3 votes
1 answer
141 views

A question related to the strong Oda conjecture

A fan is a collection of strongly convex rational polyhedral cones in $\mathbb Z^n$, which we often think of as contained in $\mathbb Q^n$ or $\mathbb R^n$ for purposes of visualizing it. The defining ...
Hugh Thomas's user avatar
  • 6,210
2 votes
1 answer
313 views

Is the blowup of a toric variety corresponding to a subdivision normal?

Toroidal Embeddings 1 by KKMS say subdividing the fan of a toric variety yields the fan of a normalized blowup. How do I avoid normalization? Do I need to choose my subdivision carefully, or is it ...
Leo Herr's user avatar
  • 1,084
2 votes
1 answer
159 views

Sections of Cartier divisors on toric varieties

Let $X_{\Sigma}$ be a projective toric variety. Consider the total coordinate ring $$S = \mathbb{C}[x_{\rho}\: | \: \rho\in\Sigma(1)]$$ Define $\deg(x_{\rho}) = D_{\rho}$. Now, take a divisor $D = \...
user avatar
3 votes
1 answer
256 views

Relation between the number of maximal cones in a fan and the geometry of corresponding toric variety

It is well known that a (smooth complete) fan $\Delta$ corresponds to a (smooth proper) toric variety $X= X_\Delta$. My question is whether there is a relationship between the number of maximal cones ...
Kazuki  Sato's user avatar
2 votes
0 answers
277 views

Is there a "fundamental theorem of toric geometry"?

I have some questions about toric geometry. 1) Can any toric variety (I mean not necessarily smooth or projective, ...) be constructed from a fan ? 2) Suppose $T_1$ and $T_2$ are toric varieties ...
THC's user avatar
  • 4,503
2 votes
2 answers
629 views

The boundary of toric varieties

Let $\mathcal{X}$ be a toric variety, with $T$ a torus embedded as an open set in $\mathcal{X}$ (and where the algebraic action of $T$ extends to $\mathcal{X}$). As I am not a toric specialist at all, ...
THC's user avatar
  • 4,503
4 votes
0 answers
281 views

Which (polytopal) fans/polytopes are secondary?

Let $P$ be a (d-1)-dimensional polytope with $n$ vertices that sits in an affine hyperplane in $\mathbb{R}^d$. The secondary fan of $P$ is a polytopal fan in $\mathbb{R}^n$ with $d$-dimensional ...
Camilo Sarmiento's user avatar