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We generalize the Generic Model Theorem for equivariant presheaves of structures; extending the results of Macintyre and Caicedo. We also introduce a new class of generic cohomologies and show how, for some examples, they simplify to non…

Logic · Mathematics 2016-04-28 Gabriel Padilla , Andres Villaveces

We prove a sampling theorem for infinite-dimensional Paley-Wiener spaces on graphs which allows for stable frame reconstruction. We prove that all sampling sets for a fixed Paley-Wiener space are complements of lambda-sets (i.e. sets where…

Functional Analysis · Mathematics 2026-05-29 Filippo Giannoni

In the case of some fractals, sampling with average values on cells is more natural than sampling on points. In this paper we investigate this method of sampling on $SG$ and $SG_{3}$. In the former, we show that the cell graph…

Analysis of PDEs · Mathematics 2015-10-07 Robert J. Ravier , Robert S. Strichartz

We introduce a notion of a sheaf of vector spaces on a graph, and develop the foundations of homology theories for such sheaves. One sheaf invariant, its "maximum excess," has a number of remarkable properties. It has a simple definition,…

Combinatorics · Mathematics 2011-06-20 Joel Friedman

Haas' theorem describes all partchworkings of a given non-singular plane tropical curve $C$ giving rise to a maximal real algebraic curve. The space of such patchworkings is naturally a linear subspace $W_C$ of the…

Algebraic Geometry · Mathematics 2023-06-22 Benoît Bertrand , Erwan Brugallé , Arthur Renaudineau

We consider the problem of offline, pool-based active semi-supervised learning on graphs. This problem is important when the labeled data is scarce and expensive whereas unlabeled data is easily available. The data points are represented by…

Machine Learning · Computer Science 2014-05-20 Akshay Gadde , Aamir Anis , Antonio Ortega

We prove some extension theorems for analytic objects, in particular sections of a coherent sheaf, defined in semi q-coronae of a complex space. Semi q-coronae are domains whose boundary is the union of a Levi flat part, a q-pseudoconvex…

Complex Variables · Mathematics 2007-05-23 Alberto Saracco , Giuseppe Tomassini

Motivated by problems in which data are given over covering generating families, we suggest a new cohomology theory for diffeological spaces, called diffeological \v{C}ech cohomology, which is an exact $ \partial $-functor of the section…

Differential Geometry · Mathematics 2023-03-07 Alireza Ahmadi

This paper affirms a conjecture of MacPherson: that the derived category of cellular sheaves is equivalent to the derived category of cellular cosheaves. We give a self-contained treatment of cellular sheaves and cosheaves and note that…

Algebraic Topology · Mathematics 2016-07-26 Justin Curry

Sheaf Neural Networks (SNNs) naturally extend Graph Neural Networks (GNNs) by endowing a cellular sheaf over the graph, equipping nodes and edges with vector spaces and defining linear mappings between them. While the attached geometric…

Machine Learning · Computer Science 2024-07-31 Ferran Hernandez Caralt , Guillermo Bernárdez Gil , Iulia Duta , Pietro Liò , Eduard Alarcón Cot

Topological filters via sheaves generalize the classical linear translation-invariant filter theory by attaching the filter computation locally to a simplicial topological space. This paper develops topological filters for causal signal…

Signal Processing · Electrical Eng. & Systems 2021-10-07 Georg Essl

We show that the space of first-order deformations of an orthogonal (resp. symplectic) sheaf over a smooth projective scheme is the first hypercohomology space of a complex which is naturally constructed out of the orthogonal (resp.…

Algebraic Geometry · Mathematics 2021-03-09 Emilio Franco

On a complex symplectic manifold we prove a finiteness result for the global sections of solutions of holonomic DQ-modules in two cases: (a) by assuming that there exists a Poisson compactification (b) in the algebraic case. This extends…

Algebraic Geometry · Mathematics 2021-05-19 Masaki Kashiwara , Pierre Schapira

In this paper we prove first a general theorem on semiorthogonal decompositions in derived categories of coherent sheaves for flat families over a smooth base. Based on the results of math.AG/0510670, we then show that the derived…

Algebraic Geometry · Mathematics 2007-05-23 Alexander Samokhin

Recent work by Abramsky and Brandenburger used sheaf theory to give a mathematical formulation of non-locality and contextuality. By adopting this viewpoint, it has been possible to define cohomological obstructions to the existence of…

Quantum Physics · Physics 2017-01-04 Giovanni Carù

Improved local and global versions of the effective Nullstellensatz for ideal sheaves on non-singular complex varieties are obtained, based on a new invariant motivated by the notion of finite type from the theory of several complex…

Algebraic Geometry · Mathematics 2007-05-23 Gordon Heier

We show that the cohomology table of any coherent sheaf on projective space is a convergent--but possibly infinite--sum of positive real multiples of the cohomology tables of what we call supernatural sheaves.

Algebraic Geometry · Mathematics 2009-02-11 David Eisenbud , Frank-Olaf Schreyer

Knowledge graph embedding involves learning representations of entities -- the vertices of the graph -- and relations -- the edges of the graph -- such that the resulting representations encode the known factual information represented by…

Machine Learning · Computer Science 2023-03-21 Thomas Gebhart , Jakob Hansen , Paul Schrater

In this paper, we mainly build up the theory of sheaf-correspondence filtered spaces and stratified de Rham complexes for studying singular spaces. We prove the finiteness of a stratified de Rham cohomology and obtain its isomorphism to…

Algebraic Geometry · Mathematics 2025-05-02 Jiaming Luo , Shirong Li

A Sheaf Neural Network (SNN) is a type of Graph Neural Network (GNN) that operates on a sheaf, an object that equips a graph with vector spaces over its nodes and edges and linear maps between these spaces. SNNs have been shown to have…