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2404.09032 2026-04-08 math.CT math.FA math.GN

Cauchy convergence in V-normed categories

Maria Manuel Clementino, Dirk Hofmann, Walter Tholen

Comments 50 pages. We correct an erroneous claim in the previous version about the category of normed vector spaces

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英文摘要

Building on the notion of normed category as suggested by Lawvere, we introduce notions of Cauchy convergence and cocompleteness which differ from proposals in previous works. Key to our approach is to treat them consequentially as categories enriched in the monoidal-closed category of normed sets. Our notions largely lead to the anticipated outcomes when considering individual metric spaces as small normed categories, but they can be challenging when considering some large categories, like those of semi-normed or normed vector spaces and all linear maps, or of generalized metric spaces and all mappings. These are the key example categories discussed in detail in this paper. Working with a general commutative quantale V as a value recipient for norms, rather than only with Lawvere's quantale of the extended real half-line, we observe that the categorically atypical structure gap between objects and morphisms in the example categories is already present in the underlying normed category of the enriching category of V-normed sets. To show that this normed category and, in fact, all presheaf categories over it, are Cauchy cocomplete, we assume the quantale V to satisfy a couple of light alternative extra properties. Of utmost importance to the general theory is the fact that our notion of normed colimit is subsumed by the notion of weighted colimit of enriched category theory. With this theory we are able to prove that all V-normed categories have correct-size Cauchy cocompletions. We also prove a Banach Fixed Point Theorem for contractive endofunctors of Cauchy cocomplete normed categories.

2404.01566 2026-04-08 econ.EM stat.ME

Heterogeneous Treatment Effects and Causal Mechanisms

Jiawei Fu, Tara Slough

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英文摘要

The credibility revolution advances the use of research designs that permit identification and estimation of causal effects. However, understanding which mechanisms produce measured causal effects remains a challenge. The dominant current approach to the quantitative evaluation of mechanisms relies on the detection of heterogeneous treatment effects (HTEs) with respect to pre-treatment covariates. This paper develops a framework to understand when the existence of such heterogeneous treatment effects can support inferences about the activation of a mechanism. We show first that this design cannot provide evidence of mechanism activation without additional, generally implicit, exclusion assumptions. Further, even when these assumptions are satisfied, the presence of HTEs supports the inference that mechanism is active but the absence of HTEs is generally uninformative about mechanism activation. We provide novel guidance for interpretation and research design in light of these findings.

2404.01498 2026-04-08 math.AP econ.TH math.OC

Existence, uniqueness, and regularity of solutions to nonlinear and non-smooth parabolic obstacle problems

Théo Durandard, Bruno Strulovici

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英文摘要

We establish the existence, uniqueness, and $W^{1,2,p}$-regularity of solutions to fully-nonlinear, parabolic obstacle problems when the obstacle is the pointwise supremum of functions in $W^{1,2,p}$ and the nonlinear operator is required only to be measurable in the state and time variables. In particular, the results hold for all convex obstacles. Applied to stopping problems, they provide general conditions under which a decision maker never stops at a convex kink of the stopping payoff. The proof relies on new $W^{1,2,p}$-estimates for obstacle problems when the obstacle is the maximum of finitely many functions in $W^{1,2,p}$.

2402.08264 2026-04-08 cs.DM math.CO

On Iiro Honkala's contributions to identifying codes

Olivier Hudry, Ville Junnila, Antoine Lobstein

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Journal ref
Fundamenta Informaticae, Volume 191, Issues 3-4: Iiro Honkala's 60 Birthday (November 10, 2024) fi:13052
英文摘要

A set $C$ of vertices in a graph $G=(V,E)$ is an identifying code if it is dominating and any two vertices of $V$ are dominated by distinct sets of codewords. This paper presents a survey of Iiro Honkala's contributions to the study of identifying codes with respect to several aspects: complexity of computing an identifying code, combinatorics in binary Hamming spaces, infinite grids, relationships between identifying codes and usual parameters in graphs, structural properties of graphs admitting identifying codes, and number of optimal identifying codes.

2401.02184 2026-04-08 math.GT

The primitive curve complex for a handlebody

Sangbum Cho, Jung Hoon Lee

Comments 16 pages, 22 figures

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Journal ref
Algebr. Geom. Topol. 26 (2026) 973-988
英文摘要

A simple closed curve in the boundary surface of a handlebody is called primitive if there exists an essential disk in the handlebody whose boundary circle intersects the curve transversely in a single point. The primitive curve complex is then defined to be the full subcomplex of the curve complex for the boundary surface, spanned by the vertices of primitive curves. Given any two primitive curves, we construct a sequence of primitive curves from one to the other one satisfying a certain property. As a consequence, we prove that the primitive curve complex for the handlebody is connected.

2401.01884 2026-04-08 cs.LO

A rewriting-logic-with-SMT-based formal analysis and parameter synthesis framework for parametric time Petri nets

Jaime Arias, Kyungmin Bae, Carlos Olarte, Peter Csaba Ölveczky, Laure Petrucci

Comments arXiv admin note: substantial text overlap with arXiv:2303.08929

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Journal ref
Fundamenta Informaticae, Volume 192, Issues 3-4: Petri Nets 2023 (November 10, 2024) fi:12781
英文摘要

This paper presents a concrete and a symbolic rewriting logic semantics for parametric time Petri nets with inhibitor arcs (PITPNs), a flexible model of timed systems where parameters are allowed in firing bounds. We prove that our semantics is bisimilar to the "standard" semantics of PITPNs. This allows us to use the rewriting logic tool Maude, combined with SMT solving, to provide sound and complete formal analyses for PITPNs. We develop and implement a new general folding approach for symbolic reachability, so that Maude-with-SMT reachability analysis terminates whenever the parametric state-class graph of the PITPN is finite. Our work opens up the possibility of using the many formal analysis capabilities of Maude -- including full LTL model checking, analysis with user-defined analysis strategies, and even statistical model checking -- for such nets. We illustrate this by explaining how almost all formal analysis and parameter synthesis methods supported by the state-of-the-art PITPN tool Romeo can be performed using Maude with SMT. In addition, we also support analysis and parameter synthesis from parametric initial markings, as well as full LTL model checking and analysis with user-defined execution strategies. Experiments show that our methods outperform Romeo in many cases.

2401.01585 2026-04-08 cs.DC cs.DM

On Completely Edge-Independent Spanning Trees in Locally Twisted Cubes

Xiaorui Li, Baolei Cheng, Jianxi Fan, Yan Wang, Dajin Wang

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Journal ref
Fundamenta Informaticae, Volume 193 (May 14, 2025) fi:12785
英文摘要

A network can contain numerous spanning trees. If two spanning trees $T_i,T_j$ do not share any common edges, $T_i$ and $T_j$ are said to be pairwisely edge-disjoint. For spanning trees $T_1, T_2, ..., T_m$, if every two of them are pairwisely edge-disjoint, they are called completely edge-independent spanning trees (CEISTs for short). CEISTs can facilitate many network functionalities, and constructing CEISTs as maximally allowed as possible in a given network is a worthy undertaking. In this paper, we establish the maximal number of CEISTs in the locally twisted cube network, and propose an algorithm to construct $\lfloor \frac{n}{2} \rfloor$ CEISTs in $LTQ_n$, the $n$-dimensional locally twisted cube. The proposed algorithm has been actually implemented, and we present the outputs. Network broadcasting in the $LTQ_n$ was simulated using $\lfloor\frac{n}{2}\rfloor$ CEISTs, and the performance compared with broadcasting using a single tree.

2401.00262 2026-04-08 math.GT math.CO math.QA

Finiteness conjecture for 3-manifolds obtained from handlebodies by attaching 2-handles

Hiroaki Karuo, Zhihao Wang

Comments 21 pages, 13 figures, Added an example in Theorem 2.13 and Appendix A

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Journal ref
Algebr. Geom. Topol. 26 (2026) 1095-1114
英文摘要

We study a generalized Witten's finiteness conjecture for the skein modules of oriented compact 3-manifolds with boundary. We formulate an equivalent version of the generalized finiteness conjecture using handlebodies and 2-handles, and prove the conjecture for some classes with the handlebodies of genus 2 and 3 using the equivalent version.

2311.11443 2026-04-08 cs.LO cs.FL

Taking Complete Finite Prefixes To High Level, Symbolically

Nick Würdemann, Thomas Chatain, Stefan Haar, Lukas Panneke

Comments This is a revised and extended version of "Nick Würdemann, Thomas Chatain, Stefan Haar: Taking Complete Finite Prefixes to High Level, Symbolically. Petri Nets 2023: 123-144"

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Journal ref
Fundamenta Informaticae, Volume 192, Issues 3-4: Petri Nets 2023 (November 10, 2024) fi:12578
英文摘要

Unfoldings are a well known partial-order semantics of P/T Petri nets that can be applied to various model checking or verification problems. For high-level Petri nets, the so-called symbolic unfolding generalizes this notion. A complete finite prefix of a P/T Petri net's unfolding contains all information to verify, e.g., reachability of markings. We unite these two concepts and define complete finite prefixes of the symbolic unfolding of high-level Petri nets. For a class of safe high-level Petri nets, we generalize the well-known algorithm by Esparza et al. for constructing small such prefixes. We evaluate this extended algorithm through a prototype implementation on four novel benchmark families. Additionally, we identify a more general class of nets with infinitely many reachable markings, for which an approach with an adapted cut-off criterion extends the complete prefix methodology, in the sense that the original algorithm cannot be applied to the P/T net represented by a high-level net.

2311.06821 2026-04-08 math.DS math.CA

Trajectories of vector fields asymptotic to formal invariant curves

Olivier Le Gal, Fernando Sanz Sánchez

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英文摘要

We prove that a formal curve $Γ$ that is invariant by a $C^\infty$ vector field $ξ$ of $\mathbb{R}^m$ has a geometrical realization, as soon as the Taylor expansion of $ξ$ is not identically zero along $Γ$. This means that there is a trajectory $γ$ of $ξ$ which is asymptotic to $Γ$. This result solves a natural question proposed by Bonckaert nearly forty years ago. We also construct an invariant $C^0$ manifold $S$ in some open horn around $Γ$ which is composed entirely of trajectories asymptotic to $Γ$, and contains the germ of any such trajectory. If $ξ$ is analytic, we prove that there exists a trajectory asymptotic to $Γ$ which is, moreover, non-oscillating with respect to subanalytic sets.

2310.09396 2026-04-08 quant-ph cond-mat.quant-gas

In situ subwavelength microscopy of ultracold atoms using dressed excited states

Romain Veyron, Jean-Baptiste Gérent, Guillaume Baclet, Vincent Mancois, Philippe Bouyer, Simon Bernon

Comments 17 pages, 11 figures

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Journal ref
PRX Quantum 5, 030349 (2024)
英文摘要

In this work, we implement a new method for imaging ultracold atoms with subwavelength resolution capabilities and determine its regime of validity. It uses the laser driven interaction between excited states to engineer hyperfine ground state population transfer in a three-level system on scales much smaller than the optical resolution. Subwavelength imaging of a quantum gas is atypical in the sense that the measurement itself perturbs the dynamics of the system. To avoid induced dynamics affecting the measurement, one usually measures "rapidly" the wavefunction in a so-called strong imaging regime. We experimentally illustrate this regime using a thermal gas ensemble, and demonstrate subwavelength resolution in quantitative agreement with a fully analytical model. Additionally, we show that, counter-intuitively, the opposite weak imaging regime can also be exploited to reach subwavelength resolution. As a proof of concept, we demonstrate that this regime is a robust solution to select and spatially resolve a 30 nm wide wavefunction, which was created and singled out from a tightly confined 1D optical lattice. Using a general dissipation-included formalism, we derive validity criteria for both regimes. The formalism is applicable to other subwavelength methods.

2308.16756 2026-04-08 math.GT

Large volume fibered knots in 3-manifolds

J. Robert Oakley

Comments 22 pages, 7 figures. Added background section and incorporated referee comments. To appear in Algebraic & Geometric Topology

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Journal ref
Algebr. Geom. Topol. 26 (2026) 955-971
英文摘要

We prove that for hyperbolic fibered knots in any closed, connected, oriented 3-manifold the volume and genus are unrelated. As an application we answer a question of Hirose, Kalfagianni, and Kin about volumes of mapping tori that are double branched covers.

2308.11056 2026-04-08 cs.DM

Closeness and Residual Closeness of Harary Graphs

Hande Tuncel Golpek, Aysun Aytac

Comments 23 pages preprint

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Journal ref
Fundamenta Informaticae, Volume 191, Issue 2 (July 8, 2024) fi:11762
英文摘要

Analysis of a network in terms of vulnerability is one of the most significant problems. Graph theory serves as a valuable tool for solving complex network problems, and there exist numerous graph-theoretic parameters to analyze the system's stability. Among these parameters, the closeness parameter stands out as one of the most commonly used vulnerability metrics. Its definition has evolved to enhance the ease of formulation and applicability to disconnected structures. Furthermore, based on the closeness parameter, vertex residual closeness, which is a newer and more sensitive parameter compared to other existing parameters, has been introduced as a new graph vulnerability index by Dangalchev. In this study, the outcomes of the closeness and vertex residual closeness parameters in Harary Graphs have been examined. Harary Graphs are well-known constructs that are distinguished by having $n$ vertices that are $k$-connected with the least possible number of edges.

2308.08927 2026-04-08 math.AG

On canonical bundle formula for fibrations of curves with arithmetic genus one

Jingshan Chen, Chongning Wang, Lei Zhang

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Journal ref
Forum of Mathematics, Sigma 14 (2026) e55
英文摘要

In this paper, we develop canonical bundle formulas for fibrations of relative dimension one in characteristic $p>0$. For such a fibration from a log pair $f\colon (X, Δ) \to S$, if $f$ is separable, we can obtain a formula similar to the one due to Witaszek \cite{Wit21}; if $f$ is inseparable, we treat the case when $S$ is of maximal Albanese dimension. As an application, we prove that for a klt pair $(X,Δ)$ with $-(K_X+Δ)$ nef, if the Albanese morphism $a_X\colon X \to A$ is of relative dimension one, then $X$ is a fiber space over $A$.

2306.16330 2026-04-08 cs.LO cs.PL

Proving Confluence in the Confluence Framework with CONFident

Raúl Gutiérrez, Salvador Lucas, Miguel Vítores

Comments Extended and revised version of our LOPSTR 2022 paper (https://doi.org/10.1007/978-3-031-16767-6_2)

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Fundamenta Informaticae, Volume 192, Issue 2: LOPSTR 2022 (November 10, 2024) fi:11515
英文摘要

This article describes the *Confluence Framework*, a novel framework for proving and disproving confluence using a divide-and-conquer modular strategy, and its implementation in CONFident. Using this approach, we are able to automatically prove and disprove confluence of *Generalized Term Rewriting Systems*, where (i) only selected arguments of function symbols can be rewritten and (ii) a rather general class of conditional rules can be used. This includes, as particular cases, several variants of rewrite systems such as (context-sensitive) *term rewriting systems*, *string rewriting systems*, and (context-sensitive) *conditional term rewriting systems*. The divide-and-conquer modular strategy allows us to combine in a proof tree different techniques for proving confluence, including modular decompositions, checking joinability of (conditional) critical and variable pairs, transformations, etc., and auxiliary tasks required by them, e.g., joinability of terms, joinability of conditional pairs, etc.

2306.08261 2026-04-08 cs.DM q-bio.MN q-bio.QM

Strong regulatory graphs

Patric Gustafsson, Ion Petre

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Journal ref
Fundamenta Informaticae, Volume 191, Issues 3-4: Iiro Honkala's 60 Birthday (November 10, 2024) fi:11473
英文摘要

Logical modeling is a powerful tool in biology, offering a system-level understanding of the complex interactions that govern biological processes. A gap that hinders the scalability of logical models is the need to specify the update function of every vertex in the network depending on the status of its predecessors. To address this, we introduce in this paper the concept of strong regulation, where a vertex is only updated to active/inactive if all its predecessors agree in their influences; otherwise, it is set to ambiguous. We explore the interplay between active, inactive, and ambiguous influences in a network. We discuss the existence of phenotype attractors in such networks, where the status of some of the variables is fixed to active/inactive, while the others can have an arbitrary status, including ambiguous.

2306.01466 2026-04-08 cs.LO

On the Complexity of Proving Polyhedral Reductions

Nicolas Amat, Silvano Dal Zilio, Didier Le Botlan

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Journal ref
Fundamenta Informaticae, Volume 192, Issues 3-4: Petri Nets 2023 (November 10, 2024) fi:12854
英文摘要

We propose an automated procedure to prove polyhedral abstractions (also known as polyhedral reductions) for Petri nets. Polyhedral abstraction is a new type of state space equivalence, between Petri nets, based on the use of linear integer constraints between the marking of places. In addition to defining an automated proof method, this paper aims to better characterize polyhedral reductions, and to give an overview of their application to reachability problems. Our approach relies on encoding the equivalence problem into a set of SMT formulas whose satisfaction implies that the equivalence holds. The difficulty, in this context, arises from the fact that we need to handle infinite-state systems. For completeness, we exploit a connection with a class of Petri nets, called flat nets, that have Presburger-definable reachability sets. We have implemented our procedure, and we illustrate its use on several examples.

2305.18288 2026-04-08 math.DS cs.SY eess.SY math.OC

Linearizability of flows by embeddings

Matthew D. Kvalheim, Philip Arathoon

Comments To appear in Selecta Mathematica

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Journal ref
Selecta Mathematica, 32.2 (2026), paper no. 38, pp. 1--22
英文摘要

We consider the problem of determining the class of continuous-time dynamical systems that can be globally linearized in the sense of admitting an embedding into a linear system on a higher-dimensional Euclidean space. We solve this problem for dynamical systems on connected state spaces that are either compact or contain at least one nonempty compact attractor, obtaining necessary and sufficient conditions for the existence of linearizing $C^k$ embeddings for $k\in \mathbb{N}_{\geq 0}\cup \{\infty\}$. Corollaries include (i) several checkable necessary conditions for global linearizability and (ii) extensions of the Hartman-Grobman and Floquet normal form theorems beyond the classical settings. Our results open new perspectives on linearizability by establishing relationships to symmetry, topology, and invariant manifold theory.

2305.18250 2026-04-08 cs.LO cs.PL

On Complexity Bounds and Confluence of Parallel Term Rewriting

Thaïs Baudon, Carsten Fuhs, Laure Gonnord

Comments Final version formatted by the editorial board. Accepted for publication in Fundamenta Informaticae, special issue for LOPSTR 2022. arXiv admin note: substantial text overlap with arXiv:2208.01005

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Journal ref
Fundamenta Informaticae, Volume 192, Issue 2: LOPSTR 2022 (November 10, 2024) fi:11397
英文摘要

We revisit parallel-innermost term rewriting as a model of parallel computation on inductive data structures and provide a corresponding notion of runtime complexity parametric in the size of the start term. We propose automatic techniques to derive both upper and lower bounds on parallel complexity of rewriting that enable a direct reuse of existing techniques for sequential complexity. Our approach to find lower bounds requires confluence of the parallel-innermost rewrite relation, thus we also provide effective sufficient criteria for proving confluence. The applicability and the precision of the method are demonstrated by the relatively light effort in extending the program analysis tool AProVE and by experiments on numerous benchmarks from the literature.

2305.18148 2026-04-08 math.CO

Two sufficient conditions for graphs to admit path factors

Sizhong Zhou, Jiancheng Wu

Comments 11 pages

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Fundamenta Informaticae, Volume 191, Issue 1 (March 30, 2024) fi:12212
英文摘要

Let $\mathcal{A}$ be a set of connected graphs. Then a spanning subgraph $A$ of $G$ is called an $\mathcal{A}$-factor if each component of $A$ is isomorphic to some member of $\mathcal{A}$. Especially, when every graph in $\mathcal{A}$ is a path, $A$ is a path factor. For a positive integer $d\geq2$, we write $\mathcal{P}_{\geq d}=\{P_i|i\geq d\}$. Then a $\mathcal{P}_{\geq d}$-factor means a path factor in which every component admits at least $d$ vertices. A graph $G$ is called a $(\mathcal{P}_{\geq d},m)$-factor deleted graph if $G-E'$ admits a $\mathcal{P}_{\geq d}$-factor for any $E'\subseteq E(G)$ with $|E'|=m$. A graph $G$ is called a $(\mathcal{P}_{\geq d},k)$-factor critical graph if $G-Q$ has a $\mathcal{P}_{\geq d}$-factor for any $Q\subseteq V(G)$ with $|Q|=k$. In this paper, we present two degree conditions for graphs to be $(\mathcal{P}_{\geq3},m)$-factor deleted graphs and $(\mathcal{P}_{\geq3},k)$-factor critical graphs. Furthermore, we show that the two results are best possible in some sense.

2305.18115 2026-04-08 math.CO math.QA math.RA

Clones of pigmented words and realizations of special classes of monoids

Samuele Giraudo

Comments 50 pages

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Journal ref
Journal of Pure and Applied Algebra, 230, Issue 4, 2026
英文摘要

Clones are specializations of operads forming powerful instruments to describe varieties of algebras wherein repeating variables are allowed in their equations. They allow us in this way to realize and study a large range of algebraic structures. A functorial construction from the category of monoids to the category of clones is introduced. The obtained clones involve words on positive integers where letters are accompanied by elements of a monoid. By considering quotients of these structures, we construct a complete hierarchy of clones involving some families of combinatorial objects. This provides clone realizations of some known and some new special classes of monoids as among others the variety of left-regular bands, bounded semilattices, and regular band monoids.

2305.16882 2026-04-08 cs.DM

Link Residual Closeness of Harary Graphs

Ch. Dangalchev

Comments 15 pages

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Journal ref
Fundamenta Informaticae, Volume 191, Issue 1 (March 30, 2024) fi:11385
英文摘要

The study of networks characteristics is an important subject in different fields, like math, chemistry, transportation, social network analysis etc. The residual closeness is one of the most sensitive measure of graphs vulnerability. In this article we calculate the link residual closeness of Harary graphs.

2305.12609 2026-04-08 cond-mat.mes-hall

Helical boundary modes from synthetic spin in a plasmonic lattice

Sang Hyun Park, Michael Sammon, Eugene Mele, Tony Low

Comments 14 pages, 5 figures, supplementary information included

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英文摘要

Artificial lattices have been used as a platform to extend the application of topological physics beyond electronic systems. Here, using the two-dimensional Lieb lattice as a prototypical example, we show that an array of disks which each support localized plasmon modes give rise to an analog of the quantum spin Hall state enforced by a synthetic time reversal symmetry. We find that an effective next-nearest-neighbor coupling mechanism intrinsic to the plasmonic disk array introduces a nontrivial $Z_2$ topological order and gaps out the Bloch spectrum. A faithful mapping of the plasmonic system onto a tight-binding model is developed and shown to capture its essential topological signatures. Full wave numerical simulations of graphene disks arranged in a Lieb lattice confirm the existence of propagating helical boundary modes in the nontrivial band gap.

2305.10038 2026-04-08 math.PR

Persistence of AR($1$) sequences with Rademacher innovations and linear mod $1$ transforms

Vladislav Vysotsky, Vitali Wachtel

Comments 50 pages

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英文摘要

We study the probability that an AR(1) Markov chain $X_{n+1}=aX_n+ξ_{n+1}$, where $a\in(0,1)$ is a constant, stays non-negative for a long time. We find the exact asymptotics of this probability and the weak limit of $X_n$ conditioned to stay non-negative, assuming that the i.i.d.\ innovations $ξ_n$ take only two values $\pm1$ and $a \le \frac23$. This limiting distribution is quasi-stationary. It has no atoms and is singular with respect to the Lebesgue measure when $\frac12< a \le \frac23$, except for the case $a=\frac23$ and $\mathbb{P}(ξ_n=1)=\frac12$, where this distribution is uniform on the interval $[0,3]$. This is similar to the properties of Bernoulli convolutions. For $0 < a \le \frac12$, the situation is much simpler, and the limiting distribution is a $δ$-measure. To prove these results, we uncover a close connection between $X_n$ killed at exiting $[0, \infty)$ and the classical dynamical system defined by the piecewise linear mapping $x \mapsto \frac1a x + \frac12 \pmod 1$. Namely, the trajectory of this system started at $X_n$ deterministically recovers the values of the killed chain in reversed time. We use this fact to construct a suitable Banach space, where the transition operator of the killed chain has the compactness properties that allow us to apply a conventional argument of the Perron--Frobenius type.

2305.07297 2026-04-08 cond-mat.stat-mech cond-mat.soft

Local measures of fluctuations in inhomogeneous liquids: Statistical mechanics and illustrative applications

Tobias Eckert, Nex C. X. Stuhlmüller, Florian Sammüller, Matthias Schmidt

Comments 17 pages, 8 figures

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Journal ref
J. Phys.: Condens. Matter 35 425102 (2023)
英文摘要

We show in detail how three one-body fluctuation profiles, namely the local compressibility, the local thermal susceptibility, and the reduced density, can be obtained from a statistical mechanical many-body description of classical particle-based systems. We present several different and equivalent routes to the definition of each fluctuation profile, facilitating their explicit numerical calculation in inhomogeneous equilibrium systems. This underlying framework is used for the derivation of further properties such as hard wall contact theorems and novel types of inhomogeneous one-body Ornstein-Zernike equations. The practical accessibility of all three fluctuation profiles is exemplified by grand canonical Monte Carlo simulations that we present for hard sphere, Gaussian core and Lennard-Jones fluids in confinement.

2305.05211 2026-04-08 math.FA math.DS math.OC math.PR

A Lagrangian approach to totally dissipative evolutions in Wasserstein spaces

Giulia Cavagnari, Giuseppe Savaré, Giacomo Enrico Sodini

Comments 100 pages

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英文摘要

We introduce and study the class of totally dissipative multivalued probability vector fields (MPVF) $\boldsymbol{\mathrm F}$ on the Wasserstein space $(\mathcal{P}_2(\mathsf{X}),W_2)$ of Euclidean or Hilbertian probability measures. We show that such class of MPVFs is in one to one correspondence with law-invariant dissipative operators in a Hilbert space $L^2(Ω,\mathcal{B},\mathbb{P};\mathsf{X})$ of random variables, preserving a natural maximality property. This allows us to import in the Wasserstein framework many of the powerful tools from the theory of maximal dissipative operators in Hilbert spaces, deriving existence, uniqueness, stability, and approximation results for the flow generated by a maximal totally dissipative MPVF and the equivalence of its Eulerian and Lagrangian characterizations. We will show that demicontinuous single-valued probability vector fields satisfying a metric dissipativity condition are in fact totally dissipative. Starting from a sufficiently rich set of discrete measures, we will also show how to recover a unique maximal totally dissipative version of a MPVF, proving that its flow provides a general mean field characterization of the asymptotic limits of the corresponding family of discrete particle systems.Such an approach also reveals new interesting structural properties for gradient flows of displacement convex functionals with a core of discrete measures dense in energy.

2305.03008 2026-04-08 math.FA

Some aspects of vector valued de Branges spaces of entire functions

Subhankar Mahapatra, Santanu Sarkar

Comments 31 pages, To appear in Computational Methods and Function Theory

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英文摘要

This paper deals with certain aspects of the vector valued de Branges spaces of entire functions that are based on pairs of Fredholm operator valued functions. Some factorization and isometric embedding results are extended from the scalar valued theory of de Branges spaces. In particular, global factorization of Fredholm operator valued entire functions and analytic equivalence of reproducing kernels of de Branges spaces are discussed. Additionally, the operator valued entire functions associated with these de Branges spaces are studied, and a connection with the operator nodes is established.

2305.02369 2026-04-08 q-bio.NC

Diffuse and Localized Functional Dysconnectivity in Schizophrenia: a Bootstrapped Top-Down Approach

Davide Coluzzi, Giuseppe Baselli

Comments 28 pages, 8 figures

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Journal ref
Fundamenta Informaticae, Volume 189, Issue 2: Tomography and Applications 2022 (September 21, 2023) fi:11275
英文摘要

Schizophrenia (SZ) is a brain disorder leading to detached mind's normally integrated processes. Hence, the exploration of the symptoms in relation to functional connectivity (FC) had great relevance in the field. FC can be investigated on different levels, going from global features to single edges between regions, revealing diffuse and localized dysconnection patterns. In this context, SZ is characterized by a diverse global integration with reduced connectivity in specific areas of the Default Mode Network (DMN). However, the assessment of FC presents various sources of uncertainty. This study proposes a multi-level approach for more robust group-comparison. FC between 74 AAL brain areas of 15 healthy controls (HC) and 12 SZ subjects were used. Multi-level analyses and graph topological indexes evaluation were carried out by the previously published SPIDER-NET tool. Robustness was augmented by bootstrapped (BOOT) data and the stability was evaluated by removing one (RST1) or two subjects (RST2). The DMN subgraph was evaluated, toegether with overall local indexes and connection weights to enhance common activations/deactivations. At a global level, expected trends were found. The robustness assessment tests highlighted more stable results for BOOT compared to the direct data testing. Conversely, significant results were found in the analysis at lower levels. The DMN highlighted reduced connectivity and strength as well as increased deactivation in the SZ group. At local level, 13 areas were found to be significantly different ($p<0.05$), highlighting a greater divergence in the frontal lobe. These results were confirmed analyzing the negative edges, suggesting inverted connectivity between prefronto-temporal areas. In conclusion, multi-level analysis supported by BOOT is highly recommended, especially when diffuse and localized dysconnections must be investigated in limited samples.

2304.14914 2026-04-08 math.GT

L-spaces, taut foliations and fibered hyperbolic two-bridge links

Diego Santoro

Comments 49 pages, 35 figures. Comments are welcome! arXiv admin note: text overlap with arXiv:2201.01211

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Journal ref
Algebr. Geom. Topol. 26 (2026) 1115-1154
英文摘要

We prove that if $M$ is a rational homology sphere that is Dehn surgery on a fibered hyperbolic two-bridge link, then $M$ is not an $L$-space if and only if $M$ supports a coorientable taut foliation. As a corollary we show that if $K'$ is obtained by a non-trivial knot $K$ as result of an operation called two-bridge replacement, then all non-meridional surgeries on $K'$ support coorientable taut foliations. This operation generalises Whitehead doubling and as a particular case we deduce that all non-meridional surgeries on Whitehead doubles of a non-trivial knot support coorientable taut foliations.

2304.08626 2026-04-08 math.OC cs.DM

On taxicab distance mean functions and their geometric applications: methods, implementations and examples

Csaba Vincze, Ábris Nagy

Comments 26 pages, 6 figures, the paper is based on the plenary lecture presented at Meeting on Tomography and Applications (Discrete Tomography, Neuroscience and Image Reconstruction) 16th Edition, IN MEMORIAM OF CARLA PERI, 2 - 4 May 2022, Mathematics Department, Politecnico di Milano, Milano, Italy

详情
Journal ref
Fundamenta Informaticae, Volume 189, Issue 2: Tomography and Applications 2022 (September 21, 2023) fi:11216
英文摘要

A distance mean function measures the average distance of points from the elements of a given set of points (focal set) in the space. The level sets of a distance mean function are called generalized conics. In case of infinite focal points the average distance is typically given by integration over the focal set. The paper contains a survey on the applications of taxicab distance mean functions and generalized conics' theory in geometric tomography: bisection of the focal set and reconstruction problems by coordinate X-rays. The theoretical results are illustrated by implementations in Maple, methods and examples as well.