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2604.24755 2026-04-28 cond-mat.str-el math-ph math.MP

Non-Abelian Particle-Loop, Fracton, and Planon Condensation in Cage-Net Models

Yifei Wang, Yu Zhao, Yingcheng Li, Hao Song, Yidun Wan

Comments 33 pages, 6 figures

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英文摘要

We present a framework for non-Abelian p-loop, fracton, and planon condensation in 3+1 dimensions by constructing extended cage-net fracton models using decoupled layers of the Hu-Geer-Wu (HGW) string-net model. These cage-net models extend the conventional cage-net models based on the Levin-Wen (LW) string-net model in the sense that they inherit the tail degrees of freedom of the HGW models, which are essential for completely describing the internal spaces of quasiparticles. This approach allows us to explicitly derive the quasiparticle spectra of the cage-net models by projecting those of the parent 2D HGW layers. Utilizing this framework, we can condense the p-loops formed by non-Abelian anyons within a fracton phase. Specifically, we construct the condensation projector for $(σ\barσ, 1)$-loops within the extended Ising Cage-Net (ICN) model. We demonstrate that condensing these non-Abelian loops drives a phase transition that maps the ICN model to the X-cube (XC) model defined on a truncated cubic lattice, a process that explicitly reveals the splitting of non-Abelian planons into distinct sub-dimensional excitations. Furthermore, our framework extends to the condensation of fractons and planons: we demonstrate that in the ICN model fracton condensation drives the decoupling of the 3D fracton order back into isolated 2D topological order layers, while planon condensation collapses the system entirely into a trivial phase. Our results establish a concrete Hamiltonian mechanism for phase transitions between distinct fracton orders and provide a generalizable method for analyzing the evolution of sub-dimensional excitations.

2604.24754 2026-04-28 math.NT

The asymptotic oscillations of moments related to Dirichlet series with missing digits

Jean-François Burnol

Comments 14 pages, 11 figures

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We prove that the (suitably rescaled) moments of certain discrete measures on the unit interval, which are related to the numerical evaluation of zeta series with missing digits in radix $b$, are asymptotically $1$-periodic in the base $b$ logarithm of the index, i.e. asymptotically invariant under multiplication by $b$ of the index.

2604.24747 2026-04-28 math.CA math.PR

A determinant identity for the sum of contour integral matrices

Zhipeng Liu, Tejaswi Tripathi

Comments 8 pages

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We derive an identity for the determinant of the sum of two $n\times n$ matrices, $A$ and $B$, whose entries are defined via contour integrals. Specifically, we consider $A(i,j)=\frac{1}{2π\mathrm{i}}\oint_0 z^{i-j-1}p_i(z)f_j(z)\mathrm{d} z$ and $B(i,j)= \frac{1}{2π\mathrm{i}}\int_Γ q_i(z)g_j(z) \mathrm{d} z$. Under suitable assumptions on the functions $p,q,f,g$, we show that $\det(A+B)$ can be expressed as a Fredholm determinant $\det(\mathrm{I} +K)$, where $K$ is an integral kernel acting on the contour $Γ$. This result generalizes a recent identity obtained in \cite{Baik-Liao-Liu26}.

2604.24743 2026-04-28 math.PR math-ph math.MP

The impact of disorder and non-convex interactions on delocalisation of height functions

Paul Dario, Diederik van Engelenburg, Christophe Garban

Comments 67 pages. Many figures

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We study the behaviour of four spins systems (the XY model, the Villain model, the XY height function and the integer-valued Gaussian free field) in the presence of a non-elliptic quenched disorder. In the article [DG25], it was shown that the phase transitions of the XY model (the Berezinskii-Kosterlitz-Thouless phase transition in $d = 2$ and the order/disorder phase transition when $d \geq 3$) persist on the infinite cluster of a supercritical Bernoulli percolation. A first objective of this article is to extend these results to the Villain model. Our second objective is to analyse, for $d=2$, how the corresponding dual integer-valued height function models behave in the presence of a dual quenched disorder. These dual models are respectively the XY height function and the integer-valued Gaussian free field. Without disorder, these models are known to exhibit a phase transition in two dimensions called the roughening transition [FS81, Lam22b]. We show that this phase transition persists when the quenched disorder is given by enforcing $φ(x) = φ(y)$ independently with probability $\bar{p} < 1/2$ for neighboring sites $x, y$. Finally, we apply our methods to integer-valued height functions with annealed Gaussian interactions and prove the existence of a (quantified) rough phase. This includes all potentials of the form $|\nabla h|^p$ for $p \in (0, 2]$, recovering recent results of [OS25].

2604.24741 2026-04-28 cond-mat.stat-mech cond-mat.soft math-ph math.MP nlin.SI

Universal tracer statistics in single-file transport

Soumyabrata Saha, Jitendra Kethepalli, Benjamin Guiselin, Jacopo De Nardis, Tridib Sadhu

Comments 9 pages, 2 figures + 13 pages of supplement

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We uncover an emergent universality in the large-scale, long-time statistics of a one-dimensional hard-rod gas evolving under two fundamentally different classes of microscopic dynamics: stochastic (diffusive) and unitary (ballistic). Remarkably, despite the difference of the two systems, the one-time joint distribution of the positions of multiple tracers exhibits identical non-Gaussian fluctuations, up to a simple dynamical scaling. This universality holds in both annealed and quenched ensembles, demonstrating a persistent memory of the initial state. Differences between the dynamics manifest at large scales only in multi-time statistics. Our conclusions are based on explicit large-deviation results for the one-time statistics of tracer pairs and the two-time statistics of a single tracer. Similar physics extends to current fluctuations, demonstrated explicitly in the quenched ensemble. We obtain these results from exact microscopic solutions for both dynamics and, independently, from fluctuating hydrodynamics in the ballistic case in the annealed ensemble. Our rare-event simulations further corroborate these findings and provide a novel demonstration of sampling atypical fluctuations in both types of hard-rod gas.

2604.24738 2026-04-28 math.OA math.FA math.GR

Invariant trace simplices and relative property (T)

Raz Slutsky

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Let $α\colon G\curvearrowright A$ be an action of a countable discrete group on a separable unital $C^*$-algebra. We study the simplex $\mathrm{T}(A)^G$ of $G$-invariant traces and ask when it is Bauer. Our main result is a noncommutative version of the Glasner-Weiss theorem: if $(G,H)$ has relative property (T) and the $H$-action on the von Neumann algebra of every extremal invariant trace is ergodic, that is, has only scalar fixed points, then $\mathrm{T}(A)^G$ is Bauer. We give criteria for the ergodicity hypothesis and apply them to certain quasi-local permutation actions, generalized Bernoulli actions, traces on group $C^*$-algebras, and reduced crossed products. In particular, if $G$ is infinite, has property (T), and trivial amenable radical, then $C_r^*(Δ\wr G)$ has Bauer trace simplex for every countable discrete group $Δ$.

2604.24736 2026-04-28 math.ST stat.TH

Parametric Statistical Inference in the Zone of Moderate Deviation Probabilities

Mikhail Ermakov

Comments 18 pages

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A parametric theory of statistical inference is developed for the moderate deviation probability zone. The new approach to the proofs is based on the Taylor series expansion of the logarithm of the likelihood ratio based on the Hellinger distance. The Large Deviation Principle in the moderate deviation probability zone is proven for Bayesian estimators and maximum likelihood estimators. A uniform approximation of the logarithm of the likelihood ratio and Theorem on concentration of the posterior Bayesian measure are also established for the zone of moderate deviation probabilities.

2604.24733 2026-04-28 math.GT math.AT

Calculating the second rational cohomology group of the Torelli group

Andrew Putman

Comments 58 pages, 30 figures

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Minahan and the author recently proved results that allow the calculation of the second rational cohomology group of the Torelli group. This builds on two key ingredients: Hain's calculation of the image of the cup product pairing on the first cohomology group, and Kupers--Randal-Williams's calculation of the maximal algebraic subrepresentation of the second cohomology group. This paper gives an exposition of both of these results, including prerequisite material about the Johnson homomorphism.

2604.24731 2026-04-28 math.NA cs.NA

Error analysis for the approximation of a flow in deformable porous media with nonlinear strain-stress relation

Andrea Bonito, Vivette Girault, Diane Guignard

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We study a model describing the slow flow of a fluid through a deformable, porous, elastic solid undergoing small deformations. The stress-strain relationship of the solid incorporates nonlinear effects, formulated as a perturbation of the classical linear elasticity. To approximate the coupled system, we introduce a discrete scheme based on a first order semi-implicit time integration scheme combined with a standard finite element spatial discretization. We establish the existence and uniqueness of the discrete solution and derive a priori convergence estimates under the assumption that the nonlinear perturbations remain sufficiently small. Finally, we demonstrate the efficiency of the proposed scheme through numerical experiments that also highlight the nonlinear phenomena captured by the model.

2604.24725 2026-04-28 math.AP

Chemotaxis compressible Navier-Stokes equations with density-dependent viscosity modeling vascular network formation

Ansgar Jüngel, Flora Philipp

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The existence of global weak solutions to the compressible Navier-Stokes equations for the density of endothelial cells and their velocity, coupled to a reaction-diffusion equation for the concentration of the chemoattractant, is established in a three-dimensional torus for energy-finite initial data. The coupling of the equations arises through the chemotaxis force, which contributes to the momentum balance equation, and the signal production due to the cells in the chemotaxis equation. The equations model the self-assembly of endothelial cells during the early stages of blood vessel formation. The existence result holds for adiabatic pressure exponents $γ>4/3$, matching the exponent found in the existence analysis for the degenerate Keller-Segel equations. The proof leverages an approximation via Korteweg and drag terms, the BD entropy inequality, and a construction of weak solutions that are renormalized in the velocity variable.

2604.24714 2026-04-28 math.AT eess.IV q-bio.NC

Homology-based Morphometry of Brain Atrophy: Methods and Applications

Donato Quiccione, Mariam Pirashvili, Nathan Broomhead, Sean J. Fallon

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Understanding the structure of the brain, and how it changes with time and disease, is a core goal of structural neuroimaging. Contemporary approaches to structural brain analysis are dominated by voxel-wise, mass-univariate methods such as voxel-based morphometry (VBM). However, these techniques require images to be normalized to a standard template, which can obscure subject-specific geometric features. Normalization to a common stereotactic space can also be problematic when comparing groups with substantial brain pathology, lesions, or other anatomical abnormalities. Here, we introduce two complementary pipelines based on persistent homology (PH), a tool from topological data analysis, to quantify multiscale geometric features of structural T1-weighted MRI scans. Pipeline 1 quantifies regional thinning by applying the Euclidean distance transform to tissue masks in a slice-wise manner. Pipeline 2 uses \(α\)-filtrations to measure structural similarity between pairs of scans, capturing sulcal widening and ventricular enlargement. Synthetic experiments with controlled induced lesions showed that Pipeline 1 is best suited to between-subject analyses, whereas Pipeline 2 is better suited to within-subject designs. Applied to real-world data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), Pipeline 1 separated Alzheimer's disease (AD) from cognitively normal (CN) participants using single-modality T1-weighted MRI without nonlinear registration (ROC-AUC = 0.895), with peak effects localized to medial temporal regions. Pipeline 2 captured disease-related longitudinal change, with follow-up scans remaining closest to their own baselines and AD subjects showing greater short-interval change than CN subjects. Together, these pipelines provide interpretable topological biomarkers for cross-sectional group comparisons and longitudinal tracking.

2604.24713 2026-04-28 math.RT math.NT

On classical doubling method gamma factors for certain depth zero representations

Johannes Girsch, Elad Zelingher

Comments 56 pages. Comments are welcome!

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Piatetski-Shapiro--Rallis discovered an integral representation construction, known as the doubling method, for the tensor product $L$-function of a cuspidal automorphic representation of $G \times \mathrm{GL}_1$, where $G$ is a classical group. Lapid--Rallis defined and studied the counterpart local factors. In this article, following Lapid--Rallis, we define and study an analogous doubling method gamma factor associated to irreducible representations of classical finite groups of Lie type. We prove that this gamma factor is multiplicative and use results of Yost-Wolff--Zelingher to give explicit formulas for it in terms of the Deligne--Lusztig data of the representation in the non-conjugate-dual character case. Finally, we relate our construction to the local construction of Lapid--Rallis via certain depth zero supercuspidal representations of classical groups.

2604.24709 2026-04-28 math.AT math.GT math.KT math.RA

A rational model for the fiberwise THH transfer II: $A_\infty$-algebras

Florian Naef, Robin Stoll

Comments 74 pages. Part II of arXiv:2604.02516, with which it shares parts of the introduction and the preliminaries. Comments welcome!

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In Part I, we proved that a rational model for the fiberwise THH transfer of a map $f$ of fibrations over a base space is given by the Hochschild homology transfer of a cdga model of $f$. In this paper, we provide an explicit description of this Hochschild homology transfer in terms of $A_\infty$-algebras, generalizing work of Bouc. Using a result of Lind-Malkiewich, we deduce a rational model for the Becker-Gottlieb transfer. We furthermore use our results for the following applications to manifold topology. Firstly, we consider the rational characteristic classes constructed by Berglund for fibrations with fiber a Poincaré complex (which generalize classes found by Berglund-Madsen); they are defined via the Lie graph complex, and we prove that the classes corresponding to non-trivalent graphs with exactly one loop vanish when evaluated on fiber bundles with fiber a compact simply connected topological manifold. Secondly, we provide a rational model for the space of fiberwise THH-simple structures, which is a step towards obtaining rational models for the classifying spaces of diffeomorphisms and homeomorphisms of a compact simply connected manifold in the rational concordance stable range.

2604.24699 2026-04-28 math.CO math.HO

Simple Matroids and Alfred North Whitehead's theory of dimension (1906)

Thomas Hales

Comments 10 pages

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We give a correspondence between simple matroids and a reconstruction of Alfred North Whitehead's theory of dimension, as developed in "On Mathematical Concepts of the Material World" (1906). In brief, if a geometrical system in the generalized sense of Whitehead has finite ground set and is phi-maximal, then it is a simple matroid. Here "generalized" means that Whitehead's three-dimensional axiom is replaced by finite-dimensionality. Conversely, every simple matroid is a phi-maximal geometrical system in the generalized sense of Whitehead.

2604.24684 2026-04-28 math.PR

Waning Immunity Fails to Restore a Positive Epidemic Threshold on Power-Law Networks

Zihao He, Souvik Dhara, Debankur Mukherjee

Comments 61 pages

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In a seminal work, Chatterjee and Durrett (2009) established that for the SIS epidemic process on random graphs with power-law degree distributions, the infection survives for an exponentially long time (in the network size) for any fixed, positive infection rate. Equivalently, the critical infection rate separating polynomial and exponential survival regimes is zero. In contrast, a substantial body of work in the physics literature conjectures, based primarily on numerical evidence and heuristic mean-field arguments, that introducing waning immunity (as in the SIRS process) yields a strictly positive critical infection rate on random graphs with power-law degrees; see, e.g., Pastor-Satorras et al. (2015), Ferreira et al. (2016), Silva et al. (2022). In particular, below this threshold, the epidemic is expected to persist only for a polynomial duration. A recent work by Friedrich et al. (2024) reinforces this perspective by proving polynomial survival for the SIRS process on star graphs, which is in contrast to the exponential survival in the SIS case that underpins Chatterjee and Durrett's arguments. In this paper, we disprove this conjecture and show that the epidemic threshold is also zero for the SIRS process on the configuration model with power-law degree distribution with exponent $τ>2$. Our proof uncovers a novel bottleneck structure for the SIRS dynamics, which we term a "hierarchical star" of order 2, and show that it sustains the infection for an exponentially long time with high probability.

2604.24682 2026-04-28 math.OA

Stable rank one, tracial local homogeneity and uniform property $Γ$

Andrea Vaccaro

Comments 24 pages

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We prove that separable, simple, unital, non-elementary, stably finite C*-algebras that have stable rank one, and that have locally finite nuclear dimension in a tracial sense, have uniform property $Γ$. In particular, Villadsen algebras of the first type and crossed products of free minimal actions of FC (in particular, abelian) groups on compact metric spaces have uniform property $Γ$. This implies that all these C*-algebras satisfy the Toms-Winter conjecture, a fact already known for C*-algebras with stable rank one and locally finite nuclear dimension, and here recovered via a different approach.

2604.24677 2026-04-28 math.PR math.CO

Local Limit of Random Regular Bipartite Planar Maps

Nicolas Tokka

Comments 19 pages, 5 figures

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We prove the existence of the local limit of uniform random d-regular bipartite planar maps, for every $d\geq 3$, as the number of vertices tends to infinity. The proof relies on a bijection between maps and so-called blossoming trees established in a previous work. After proving local convergence of the associated decorated trees, we extend the bijection to infinite trees and transfer the convergence to planar maps. The limiting object is almost surely one-ended and recurrent for the simple random walk.

2604.24676 2026-04-28 math.GR

Fusion Systems on Sylow $3$-subgroups of Fischer and Monster sporadic groups: I

Pete Gautam

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We classify all corefree fusion systems on a Sylow $3$-subgroup of the sporadic groups $\mathrm{Fi}_{22}$, $\mathrm{Fi}_{23}$ and $\mathrm{B}$. We show that the $3$-group in each case does not support any exotic fusion systems. This is the first of two papers that will complete the classification of all corefree fusion systems on Sylow $p$-subgroups of sporadic groups for $p$ odd.

2604.24672 2026-04-28 cs.LG math.AT

A Functorial Formulation of Neighborhood Aggregating Deep Learning

Sun Woo Park, Yun Young Choi, U Jin Choi, Youngho Woo

Comments 32 pages, 11 figures. Comments welcome

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We provide a mathematical interpretation of convolutional (or message passing) neural networks by using presheaves and copresheaves of the set of continuous functions over a topological space. Based on this interpretation, we formulate a theoretical heuristic which elaborates a number of empirical limitations of these neural networks by using obstructions on such sets of continuous functions over a topological space to be sheaves or copresheaves.

2604.24667 2026-04-28 math.AG math.CO

Principal Matroid Determinants

Saiei-Jaeyeong Matsubara-Heo, Simon Telen

Comments 34 pages, 3 figures

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We develop a theory of principal determinants and hypergeometric systems for realizable matroids. Our framework parallels the toric theory of Gel'fand, Kapranov, and Zelevinsky (GKZ), but with the combinatorics of matroids and their flats replacing the usual role of polytopes and their faces. In this analogy, the toric variety is replaced by a reciprocal linear space. The {principal $A$-determinant} is replaced by the {principal matroid determinant}, defined as a specialization of a resultant. The GKZ hypergeometric system is replaced by the {matroid hypergeometric system}, a holonomic $D$-module of combinatorial nature whose singular locus is conjectured to be the principal matroid~determinant.

2604.24664 2026-04-28 math.PR

Absolute continuity of Rosenblatt measures

Petr Čoupek, Tyrone E. Duncan, Bozenna Pasik-Duncan, Jakub Slavík

Comments 14 pages

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In the article, we address the problem of absolute continuity of translated Rosenblatt measures on the path space. In [Čoupek, P., Kříž, P., Maslowski, B., Stoch. Proc. Appl. 179 (2025) art. no. 104499], it is shown that there is no probability measure that would be equivalent to the original probability measure and under which a Rosenblatt path with a linear drift would again be a Rosenblatt path. Here, we show that if the Rosenblatt path is shifted in a direction belonging to a class of nontrivial Gaussian variables (that consists of a deterministic shift and a Wiener integral with respect to a fractional Brownian motion with a related Hurst parameter), such a measure exists. We also give several examples to demonstrate the scope of the result.

2604.24663 2026-04-28 math.OC cs.LG cs.SY eess.SY

Dual Control of Linear Systems from Bilinear Observations with Belief Space Model Predictive Control

Daniel Cao, Beixi Du, Andrew Lowitt, Sunmook Choi, Sarah Dean, Yahya Sattar

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We study finite-horizon quadratic control of linear systems with bilinear observations, in which the control input affects not only the state dynamics but also the partial observations of the state. In this setting, the separation principle can fail because control inputs influence the future quality of state estimates. State estimation requires an input-dependent Kalman filter whose gain and error covariance evolve as functions of the control inputs. To address this challenge, we propose a belief-space model predictive control ($\texttt{B-MPC}$) method that plans directly over both the estimated state and its error covariance. In particular, $\texttt{B-MPC}$ plans with a deterministic surrogate of the belief evolution defined by the input-dependent Kalman filter. Through numerical experiments in two synthetic settings, we show that $\texttt{B-MPC}$ can outperform both the separation-principle controller and its MPC variant in favorable regimes, and that these gains are accompanied by lower estimation covariance and more uncertainty-aware action choices.

2604.24656 2026-04-28 cs.IT math.IT

Densification Converses for Walker Constellations With Explicit Constants and Reuse Scaling Laws

Ali Khalesi, François Baccelli

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We establish densification converses for Walker LEO constellations under nearest-visible association in the full-frequency-reuse setting. Performance is evaluated under the invariant (stationary) measure induced by the constellation/Earth dynamics on the user--constellation ``phase state.'' A key Walker-specific feature, absent from unbounded planar models, is that association is restricted to a bounded visible cap determined by Earth geometry. Under power-law path-loss, a two-level antenna-gain model, i.i.d.\ nonnegative fading with unit mean and finite second moment, and nonzero noise, we prove that increasing the total satellite count $N=N_oN_s$ forces the aggregate interference to grow at least linearly in $N$, while the useful signal remains uniformly bounded above. Consequently, the downlink SINR coverage probability at any fixed threshold and the ergodic spectral efficiency both vanish as $N\to\infty$. The key technical ingredient is a deterministic visibility-annulus block lemma, uniform over all sufficiently large constellations and all "phase states", showing that a fixed fraction of visible satellites lies in a distance annulus strictly inside the horizon; this yields explicit finite-$N$ collapse bounds. In particular, we derive nonasymptotic $O(1/N)$ upper bounds on both coverage and ergodic spectral efficiency. Finally, in the case of frequency reuse through independent thinning, with activity probability $q$, we show that avoiding densification collapse necessarily requires $qN=O(1)$, equivalently a reuse factor $Ω(N)$, and we obtain a corresponding explicit $O(1/(qN))$ upper bound.

2604.24650 2026-04-28 math.NT

On $k$-th power Diophantine triples of the form $\{a^k, b, c\}$

Clemens Fuchs, Miriam Schönauer

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In this paper, we prove that there are no $k$-th power Diophantine triples of the form $\{a^k,b,c\}$ for $k\geq 3$ and $1<a^k<b<c$.

2604.24638 2026-04-28 math.RA

$k$-step nilpotent symplectic Lie algebras associated with graphs

Josefina Barrionuevo, Paulo Tirao, Sonia Vera

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We construct families of $k$-step nilpotent symplectic Lie algebras associated with graphs, extending the construction given in [Pouseele-Tirao, JPAA 213 (2009)] for the 2-step case. We also show that, under mild conditions on the nilpotency type, there exist symplectic Lie algebras of that type.

2604.24632 2026-04-28 stat.CO cs.NA math.NA math.PR

Theoretical guarantees for stochastic gradient sampling methods via Gaussian convolution inequalities

Daniel Paulin, Peter A. Whalley

Comments 34 pages, 2 figures

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We derive first-order (in the stepsize) bounds on the bias in Wasserstein distances of the invariant measure of stochastic gradient kinetic Langevin dynamics with minimal assumptions on the stochastic gradient noise. These bounds sharpen existing non-asymptotic guarantees for stochastic-gradient MCMC methods and provide a quantitative resolution of a previously open problem on invariant measure accuracy. The main technical ingredients are new Gaussian convolution inequalities controlling the Wasserstein-$p$ distance between a Gaussian convolved with a mean-zero perturbation and the Gaussian itself. We anticipate that these inequalities will be of independent interest beyond the present application.

2604.24624 2026-04-28 math.PR

Limit distributions of the threshold radius for the maximum degree and the associated point configurations in random geometric graphs

Junpei Otsuka

Comments 19 pages

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A random geometric graph $G(\mathcal{X}_n, r_n)$ is formed by taking a binomial process $\mathcal{X}_n$ as the set of vertices and joining any two distinct points with an edge if they lie within distance $r_n$ of each other. We investigate the limit distribution of the threshold radius for which the maximum degree of the graph is at least a given value that depends on $n$. In addition, given the radii $(r_n)_{n \in \mathbf{N}}$, we examine the limiting behavior of the point process formed by the vertices that achieve the maximum degree. Roughly speaking, the limiting process exhibits a compound Poisson behavior in the regime where the maximum degree remains bounded, due to local geometric dependencies, whereas it exhibits a Poisson behavior in the regime where the maximum degree diverges more slowly than $\log n$.

2604.24619 2026-04-28 math.GT math.DS math.GR math.PR

CaTherine wheels

Danny Calegari, Ino Loukidou

Comments 81 pages, 35 figures

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A CaTherine wheel is a surjective continuous map $f:S^1 \to S^2$ such that for every closed interval $I\subset S^1$ the image $f(I)$ is homeomorphic to a disk, and $f(\partial I)$ is contained in the boundary of this disk. CaTherine wheels arise in many areas of low-dimensional geometry and topology, including conformal dynamics (expanding Thurston maps, expanding origamis), probability theory (whole plane ${\rm SLE}_κ$ for $κ\ge 8$, LQG metric trees) and elsewhere. We develop their theory in generality, and explain how CaTherine wheels and their associated structures can serve as a dictionary between these various fields. Our most substantial applications are to the theory of hyperbolic 3-manifolds. If $M$ is a closed hyperbolic 3-manifold and $G=π_1(M)$, we show that there is a canonical bijection between four kinds of structures associated to $M$: 1. orbit-equivalence classes of pseudo-Anosov flows on $M$ without perfect fits; 2. $G$-equivariant CaTherine wheels up to conjugacy; 3. minimal $G$-zippers; and 4. connected components of the space of uniform quasimorphisms on $G$. This generalizes and amplifies the theory of fiberings of hyperbolic 3-manifolds over the circle and the Thurston norm.

2604.24612 2026-04-28 cs.AI cs.LO math.CT math.LO

NeSyCat: A Monad-Based Categorical Semantics of the Neurosymbolic ULLER Framework

Daniel Romero Schellhorn, Till Mossakowski

Comments 42 pages. Submitted to Neurosymbolic Artificial Intelligence (IOS Press), after extending from a conference paper of NeSy25

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ULLER (Unified Language for LEarning and Reasoning) offers a unified first-order logic (FOL) syntax, enabling its knowledge bases to be used directly across a wide range of neurosymbolic systems. The original specification endows this syntax with three pairwise independent semantics: classical, fuzzy, and probabilistic, each accompanied by dedicated semantic rules. We show that these seemingly disparate semantics are all instances of one categorical framework based on monads, the very construct that models side effects in functional programming. This enables the modular addition of new semantics and systematic translations between them. As example, we outline the addition of generalised quantification in Logic Tensor Networks (LTN) to arbitrary (also infinite) domains by extending the Giry monad to probability spaces. In particular, our approach allows a modular implementation of ULLER in Python and Haskell, of which we have published initial versions on GitHub.

2604.24605 2026-04-28 math.OC

PRP, HS and LS Conjugate Gradient Methods for Interval-Valued Multiobjective Optimization Problems

Tapas Mondal, Debdulal Ghosh, Zai-Yun Peng, Yong Zhao

Comments 26 pages, 3 figures, and 2 tables

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In this article, we develop an efficient algorithm based on three special variants of the nonlinear conjugate gradient method, namely, the Polak--Ribiere--Polyak, Hestenes--Stiefel, and Liu--Story schemes for computing Pareto critical points in unconstrained interval-valued multiobjective optimization problems. The proposed algorithm incorporates a Wolfe line search strategy to determine a suitable range of step size that satisfies the standard Wolfe conditions. For each of the proposed variants of the nonlinear conjugate gradient method, we establish rigorous global convergence results under appropriate assumptions. To demonstrate the effectiveness of the proposed methods, we conduct numerical experiments on a set of benchmark test problems and present a comprehensive performance profile analysis.