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Question 1. Can a reflexive Delzant polytope of some dimension contain a $2$-face with more than $11$ edges?

Motivation. I would like more generally to get an answer to the following question:

Question 2. Suppose $X$ is a smooth Fano variety with a $\mathbb C^*$-action. Let $Y\subset X$ be the connected component of $X^{\mathbb C^*}$ on which all the weights of the action are positive. Is it true that variety $Y$ can be deformed to a Fano variety?

Obviously,A positive answer to the first question gives a negative to the second one.

Explanation. Indeed, a reflexive Delzant polytope by definition corresponds to a toric Fano. For any face of a Delzant polytope we can find a rational linear support function. This will give us a $\mathbb C^*$ action as in Question 2. A surface that deforms to a Fano surface has $b_2\le 9$. Finally, a toric surface corresponding to a polygon with $n$ sides has $b_2=n-2$.

Question 1. Can a reflexive Delzant polytope of some dimension contain a $2$-face with more than $11$ edges?

Motivation. I would like more generally to get an answer to the following question:

Question 2. Suppose $X$ is a smooth Fano variety with a $\mathbb C^*$-action. Let $Y\subset X$ be the connected component of $X^{\mathbb C^*}$ on which all the weights of the action are positive. Is it true that variety $Y$ can be deformed to a Fano variety?

Obviously, positive answer to the first question gives a negative to the second one.

Question 1. Can a reflexive Delzant polytope of some dimension contain a $2$-face with more than $11$ edges?

Motivation. I would like more generally to get an answer to the following question:

Question 2. Suppose $X$ is a smooth Fano variety with a $\mathbb C^*$-action. Let $Y\subset X$ be the connected component of $X^{\mathbb C^*}$ on which all the weights of the action are positive. Is it true that variety $Y$ can be deformed to a Fano variety?

A positive answer to the first question gives a negative to the second one.

Explanation. Indeed, a reflexive Delzant polytope by definition corresponds to a toric Fano. For any face of a Delzant polytope we can find a rational linear support function. This will give us a $\mathbb C^*$ action as in Question 2. A surface that deforms to a Fano surface has $b_2\le 9$. Finally, a toric surface corresponding to a polygon with $n$ sides has $b_2=n-2$.

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aglearner
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Question 1. Can a reflexive Delzant polytope of some dimension contain a $2$-face with more than $11$ edges?

Motivation. I would like more generally to get an answer to the following question:

Question 2. Suppose $X$ is a smooth Fano variety with a $\mathbb C^*$-action. Let $Y\subset X$ be the connected component of $X^{\mathbb C^*}$ on which all the weights of the action are positive. Is it true that variety $Y$ can be deformed to a Fano variety?

Obviously, positive answer to the first question gives a negative to the second one.

Can a reflexive Delzant polytope of some dimension contain a $2$-face with more than $11$ edges?

Question 1. Can a reflexive Delzant polytope of some dimension contain a $2$-face with more than $11$ edges?

Motivation. I would like more generally to get an answer to the following question:

Question 2. Suppose $X$ is a smooth Fano variety with a $\mathbb C^*$-action. Let $Y\subset X$ be the connected component of $X^{\mathbb C^*}$ on which all the weights of the action are positive. Is it true that variety $Y$ can be deformed to a Fano variety?

Obviously, positive answer to the first question gives a negative to the second one.

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aglearner
  • 14.3k
  • 8
  • 40
  • 99

2-faces of reflexive Delzant polytopes

Can a reflexive Delzant polytope of some dimension contain a $2$-face with more than $11$ edges?