Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userThe Hilbert compactification of the universal moduli space of semistable vector bundles over smooth curves
127
0
0.0
(
0
)
Authors
Alexander Schmitt
Ask ChatGPT about the research
No Arabic abstract
We construct the Hilbert compactification of the universal moduli space of semistable vector bundles over smooth curves. The Hilbert compactification is the GIT quotient of some open part of an appropriate Hilbert scheme of curves in a Grassmannian. It has all the properties asked for by Teixidor.
rate research
Read More
Let $X$ be a smooth projective curve over the complex numbers. To every representation $rhocolon GL(r)lra GL(V)$ of the complex general linear group on the finite dimensional complex vector space $V$ which satisfies the assumption that there be an integer $alpha$ with $rho(z id_{C^r})=z^alpha id_V$ for all $zinC^*$ we associate the problem of classifying triples $(E,L,phi)$ where $E$ is a vector bundle of rank $r$ on $X$, $L$ is a line bundle on $X$, and $phicolon E_rholra L$ is a non trivial homomorphism. Here, $E_rho$ is the vector bundle of rank $dim V$ associated to $E$ via $rho$. If we take, for example, the standard representation of $GL(r)$ on $C^r$ we have to classify triples $(E,L,phi)$ consisting of $E$ as before and a non-zero homomorphism $phicolon Elra L$ which includes the so-called Bradlow pairs. For the representation of $GL(r)$ on $S^2C^3$ we find the conic bundles of Gomez and Sols. In the present paper, we will formulate a general semistability concept for the above triples which depends on a rational parameter $delta$ and establish the existence of moduli spaces of $delta$-(semi)stable triples of fixed topological type. The notion of semistability mimics the Hilbert-Mumford criterion for $SL(r)$ which is the main reason that such a general approach becomes feasible. In the known examples (the above, Higgs bundles, extension pairs, oriented framed bundles) we show how to recover the usual semistability concept. This process of simplification can also be formalized. Altogether, our results provide a unifying construction for the moduli spaces of most decorated vector bundle problems together with an automatism for finding the right notion of semistability and should therefore be of some interest.
Let $X$ be a smooth projective curve of genus $g geq 2$ and $M$ be the moduli space of rank 2 stable vector bundles on $X$ whose determinants are isomorphic to a fixed odd degree line bundle $L$. There has been a lot of works studying the moduli and recently the bounded derived category of coherent sheaves on $M$ draws lots of attentions. It was proved that the derived category of $X$ can be embedded into the derived category of $M$ by the second named author and Fonarev-Kuznetsov. In this paper we prove that the derived category of the second symmetric product of $X$ can be embedded into derived category of $M$ when $X$ is non-hyperelliptic and $g geq 16$.
We show a few basic results about moduli spaces of semistable modules over Lie algebroids. The first result shows that such moduli spaces exist for relative projective morphisms of noetherian schemes, removing some earlier constraints. The second result proves general separatedness Langton type theorem for such moduli spaces. More precisely, we prove S-completness of some moduli stacks of semistable modules. In some special cases this result identifies closed points of the moduli space of Gieseker semistable sheaves on a projective scheme and of the Donaldson--Uhlenbeck compactification of the moduli space of slope stable locally free sheaves on a smooth projective surface. The last result generalizes properness of Hitchins morphism and it shows properness of so called Hodge-Hitchin morphism defined in positive characteristic on the moduli space of Gieseker semistable integrable t-connections in terms of the p-curvature morphism. This last result was proven in the curve case by de Cataldo and Zhang using completely different methods.
We investigate degenerations of syzygy bundles on plane curves over $p$-adic fields. We use Mustafin varieties which are degenerations of projective spaces to find a large family of models of plane curves over the ring of integers such that the special fiber consists of multiple projective lines meeting in one point. On such models we investigate vector bundles whose generic fiber is a syzygy bundle and which become trivial when restricted to each projective line in the special fiber. Hence these syzygy bundles have strongly semistable reduction. This investigation is motivated by the fundamental open problem in $p$-adic Simpson theory to determine the category of Higgs bundles corresponding to continuous representations of the etale fundamental group of a curve. Faltings $p$-adic Simpson correspondence and work of Deninger and the second author shows that bundles with Higgs field zero and potentially strongly semistable reduction fall into this category. Hence the results in the present paper determine a class of syzygy bundles on plane curves giving rise to a $p$-adic local system. We apply our methods to a concrete example on the Fermat curve suggested by Brenner and prove that this bundle has potentially strongly semistable reduction.
We prove an explicit formula for the total Chern character of the Verlinde bundle over the moduli space of pointed stable curves in terms of tautological classes. The Chern characters of the Verlinde bundles define a semisimple CohFT (the ranks, given by the Verlinde formula, determine a semisimple fusion algebra). According to Telemans classification of semisimple CohFTs, there exists an element of Giventals group transforming the fusion algebra into the CohFT. We determine the element using the first Chern class of the Verlinde bundle on the moduli space of nonsingular curves and the projective flatness of the Hitchin connection.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
