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We provide explicit graded constructions of orbifold del Pezzo surfaces with rigid orbifold points of type $\left\{k_i\times\frac{1}{r_i}(1,a_i): 3\le r_i \le 10,k_i \in \ZZ_{\ge 0}\right\}$; as well-formed and quasismooth varieties…

Algebraic Geometry · Mathematics 2020-09-14 Muhammad Imran Qureshi

We present new constructions of Kaehler metrics with constant scalar curvature on complex surfaces, in particular on certain del Pezzo surfaces. Some higher dimensional examples are provided as well.

Differential Geometry · Mathematics 2007-05-23 Yann Rollin , Michael A. Singer

An I-surface $S$ is an algebraic surface of general type with $K_S^2 = 1$ and $p_g(S) = 2$. Recent research has centered on trying to give an explicit description of the KSBA compactification of the moduli space of these surfaces. The…

Algebraic Geometry · Mathematics 2024-03-15 Robert Friedman , Phillip Griffiths

We develop a framework to study the K-stability of weighted Fano hypersurfaces based on a combination of birational and convex-geometric techniques. As an application, we prove that all quasi-smooth weighted Fano hypersurfaces of index 1…

Algebraic Geometry · Mathematics 2026-01-07 Livia Campo , Kento Fujita , Taro Sano , Luca Tasin

In this paper, we study biconservative hypersurfaces of index 2 in $\mathbb E^{5}_{2}$. We give the complete classification of biconservative hypersurfaces with diagonalizable shape operator at exactly three distinct principal curvatures.…

Differential Geometry · Mathematics 2016-09-07 Abhitosh Upadhyay , Nurettin Cenk Turgay

In this article we prove the following theorems about weak approximation of smooth cubic hypersurfaces and del Pezzo surfaces of degree 4 defined over global fields. (1) For cubic hypersurfaces defined over global function fields, if there…

Algebraic Geometry · Mathematics 2015-11-26 Letao Zhang , Zhiyu Tian

We prove that the alpha invariant of a quasi-smooth Fano 3-fold weighted hypersurface of index $1$ is greater than or equal to $1/2$. Combining this with the result of Stibitz and Zhuang \cite{SZ19} on a relation between birational…

Algebraic Geometry · Mathematics 2023-08-29 In-Kyun Kim , Takuzo Okada , Joonyeong Won

We give the first evidence for a conjecture that a general, index-one, Fano hypersurface is not unirational: (i) a general point of the hypersurface is contained in no rational surface ruled, roughly, by low-degree rational curves, and (ii)…

Algebraic Geometry · Mathematics 2007-05-23 Roya Beheshti , Jason Michael Starr

We introduce a mock toric variety, a generalization of a toric variety. For a non-toric example, Del-Pezzo surfaces are mock toric varieties. These new varieties inherit some properties of mock toric varieties. In application, we give…

Algebraic Geometry · Mathematics 2024-05-22 Taro Yoshino

We construct from a general del Pezzo surface of degree 1 a Gorenstein stable surfaces $X$ with $K_X^2=1$ and $p_g(X)=q(X)=0$. These surfaces are not smoothable but give an open subset of an irreducible component of the moduli space of…

Algebraic Geometry · Mathematics 2014-04-29 Sönke Rollenske

We consider del Pezzo surfaces with du Val singularities. We'll prove that a del Pezzo surface $X$ with du Val singularities has a $-K_X$-polar cylinder if and only if there exist tiger such that the support of this tiger does not contain…

Algebraic Geometry · Mathematics 2018-10-16 Grigory Belousov

We consider the problem of interpolating projective varieties through points and linear spaces. We show that del Pezzo surfaces satisfy weak interpolation.

Algebraic Geometry · Mathematics 2020-04-14 Aaron Landesman , Anand Patel

We complete the classification of local stability thresholds for smooth del Pezzo surfaces of degree~2. In particular, we show that this number is irrational if and only if a unique (-1)-curve passes through the point where we are computing…

Algebraic Geometry · Mathematics 2024-08-12 Erroxe Etxabarri Alberdi

For a regular del Pezzo surface $X$, we prove that $|-12K_X|$ is very ample. Furthermore, we also give an explicit upper bound for the volume $K_X^2$ which depends only on $[k : k^p]$ for the base field $k$. As a consequence, we obtain the…

Algebraic Geometry · Mathematics 2023-10-26 Hiromu Tanaka

We show that the pair $(X, -K_X)$ is K-unstable for a del Pezzo manifold $X$ of degree five with dimension four or five. This disprove a conjecture of Odaka and Okada.

Algebraic Geometry · Mathematics 2015-08-21 Kento Fujita

We consider del Pezzo surfaces $X$ with du Val singularities. Assume that $X$ has a $-K_X$-polar cylinder and $\deg X=1$. Let $H$ be an ample divisor. We'll prove that $X$ has a $H$-polar cylinder.

Algebraic Geometry · Mathematics 2025-12-17 Grigory Belousov , Nivedita Viswanathan

For each del Pezzo surface $S$ with du Val singularities, we determine whether it admits a $(-K_S)$-polar cylinder or not. If it allows one, then we present an effective $\mathbb{Q}$-divisor $D$ that is $\mathbb{Q}$-linearly equivalent to…

Algebraic Geometry · Mathematics 2019-02-20 Ivan Cheltsov , Jihun Park , Joonyeong Won

We use classification of non-symplectic automorphisms of K3 surfaces to obtain a partial classification of log del Pezzo surfaces of index three. We can classify those with "Multiple Smooth Divisor Property", whose definition we will give.…

Algebraic Geometry · Mathematics 2012-03-27 Hisanori Ohashi , Shingo Taki

We prove the failure of stable rationality for many smooth well formed weighted hypersurfaces of dimension at least 3. It is in particular proved that a very general smooth well formed Fano weighted hypersurface of index one is not stably…

Algebraic Geometry · Mathematics 2017-09-26 Takuzo Okada

We consider a real del Pezzo surface without points. We prove that the same surface over complex numbers field $\mathbb{C}$ has Picard number is at least two.

Algebraic Geometry · Mathematics 2024-12-17 Grigory Belousov