We study irreducible holomorphic symplectic manifolds deformation equivalent to Hilbert schemes of points on a $K3$ surface and admitting a non-symplectic involution. We classify the possible discriminant forms of the invariant and anti-invariant lattice for the action of the involution on cohomology, and explicitly describe the lattices in the cases where the invariant has small rank. We also give a modular description of all $d$-dimensional families of manifolds of $K3^{[n]}$-type with a non-symplectic involution for $d\geq 19$ and $n\leq 5$, and provide examples arising as moduli spaces of twisted sheaves on a $K3$ surface.
There are three types of involutions on a cubic fourfold; two of anti-symplectic type, and one symplectic. Here we show that cubics with involutions exhibit the full range of behaviour in relation to rationality conjectures. Namely, we show a general cubic fourfold with symplectic involution has no associated K3 surface and is conjecturely irrational. In contrast, we show a cubic fourfold with a particular anti-symplectic involution has an associated K3, and is in fact rational. We show such a cubic is contained in the intersection of all non-empty Hassett divisors; we call such a cubic Hasset…
We study the boundary behavior of the invariant of $K3^{[2]}$-type manifolds with antisymplectic involution, which we obtained using equivariant analytic torsion. We show the algebraicity of the singularity of the invariant by using the asymptotic of equivariant Quillen metrics and equivariant $L^2$-metrics. We prove that, in some cases, the invariant coincides with Yoshikawa's invariant for 2-elementary K3 surfaces. Hence, in these cases, our invariant is expressed as the Petersson norm of a Borcherds product and a Siegel modular form.
Verra fourfolds, twisted sheaves and the last involution
研究了K3曲面上扭层的某些模空间的几何性质。特别地，我们引入诱导自同构从一个K3表面上的扭曲层的模空间在这个K3表面上。作为应用，我们证明了具有不变格$U(2)\oplus D_4(-1)$或$U(2)\oplus E_8(-2)$的非辛对合的不可约$K3^{[2]}$型全纯辛流形的模空间的单合理性.这补充了[Mongardi and Wandel 2015]，[Bossiere et al 2016]中获得的结果，以及[arXiv：1603.00403]中关于使用Verra四重曲线上$(1,1)$二次曲线的Hilbert方案构建IHS四重曲线几何的结果。作为一个副产品，我们发现，IHS四倍的$K3^{[2]}$型皮卡德格$U(2)\oplus E_8(-2)$自然包含非节Enriques曲面。
The concept of non-Gorenstein involutions on Calabi-Yau threefolds is a higher dimensional generalization of non-symplectic involutions on $K3$ surfaces. We present some elementary facts about Calabi-Yau threefolds with non-Gorenstein involutions. We give a classification of the Calabi-Yau threefolds of Picard rank one with non-Gorenstein involutions whose fixed locus is not zero-dimensional.
Starting from an anti-symplectic involution on a K3 surface, one can consider a natural Lagrangian subvariety inside the moduli space of sheaves over the K3. One can also construct a Prymian integrable system following a construction of Markushevich--Tikhomirov, extended by Arbarello--Saccà--Ferretti, Matteini and Sawon--Chen. In this article we address a question of Sawon, showing that these integrable systems and their associated natural Lagrangians degenerate, respectively, into fix loci of involutions considered by Heller--Schaposnik, Garcia-Prada--Wilkins and Basu--Garcia-Prada. Along the…
Real K3 surfaces with non-symplectic involution and applications. II
考虑相对极小有理曲面F_m的实形式。中实非奇异曲线模的连通分量|K_{F_m}|最近在数学中被分类为m=0，1，4。AG/0312396。应用类似的方法，在这里，我们填补了m=2和m=3的空白，以完成对任何0 \le m \le 4的类似分类，|K_{F_m}|减少了。F_2的情形尤其显著和经典（P^3中的二次锥）。作为应用，我们完成了从数学AG/0312396，数学AG/0507197开始的实超椭圆极化K3曲面模的连通分量的分类及其对实极化K3曲面的变形。这在某些问题中可能是重要的，因为可以明确地构造真实的超椭圆偏振K3表面。
Lusztig defined certain involutions on the equivariant K-theory of Slodowy varieties and gave a characterization of certain bases called canonical bases. In this paper, we give a conjectural generalization of these involutions and K-theoretic canonical bases to conical symplectic resolutions which have good Hamiltonian torus actions and state several conjectures related to them which we check for toric hyper-Kahler manifolds. We also propose an elliptic analogue of these bar involutions. As a verification of our proposal, we explicitly construct elliptic lifts of K-theoretic canonical bases an…
Consider a Maslov zero Lagrangian submanifold diffeomorphic to a Lie group on which an anti-symplectic involution acts by the inverse map of the group. We show that the Fukaya $A_\infty$ endomorphism algebra of such a Lagrangian is quasi-isomorphic to its de Rham cohomology tensored with the Novikov field. In particular, it is unobstructed, formal, and its Floer and de Rham cohomologies coincide. Our result implies that the smooth fibers of a large class of singular Lagrangian fibrations are unobstructed and their Floer and de Rham cohomologies coincide. This is a step in the SYZ and family Fl…
