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Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.

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arXiv2026

Query-Conditioned Liquid Temporal Grounding for Long-Form Audio

Long-form temporal audio grounding (TAG) is challenging because target events often occupy only a small portion of a recording, while queries may impose multiple semantic constraints over a large temporal search space. We propose a query-conditioned liquid temporal grounding framework that injects query semantics through FiLM before a closed-form continuous-time (CfC) network models long-range temporal dependencies. Multiple query-relevant candidates are generated, from which a frozen large audio-language model selects the most compatible one for lightweight local boundary refinement. The pretrained backbone remains frozen, with only lightweight grounding modules optimized. Experiments on the English TAG subset of LAT-Bench show consistent improvements across MOSS-Audio and Qwen3-Omni, while ablations confirm the complementary roles of FiLM and CfC.

cs.SD↗

arXiv2026

Reinforcing intra-operative tumour localisation with weak supervision from pre-operative appearances

Limited tumour visibility on intra-operative images complicates surgical navigation, including liver hepatocellular carcinoma (HCC) targeting on computed tomography (CT) imaging. This makes labelled datasets difficult to curate for deep learning, and transferring pre-operative delineations through registration remains challenging due to intra-operative deformation and lack of paired pre- and intra-operative data. We propose to transfer tumour appearances learned from pre-operative magnetic resonance (MR) images to guide localisation on intra-operative CT through weak supervision. A classifier is trained to classify tumour presence on pre-operative images. This is applied to windows on intra-operative images, and despite the domain gap, it assigns higher tumour-presence probabilities on average to tumour-containing windows. These weak cross-domain signals guide a reinforcement learning agent to localise tumours on intra-operative images. We compare direct transfer, few-shot adaptation and synthetic transfer (trained using unpaired MR and CT), which translates CT into synthetic MR before localisation. On an external HCC cohort, synthetic transfer outperformed other tested methods and CT-only baselines. Our framework enables cross-modality tumour localisation without paired MR-CT training images.

cs.CV↗

arXiv2026

A consistent neutrino determination of the low-energy weak mixing angle

The weak mixing angle, $\sin^2θ_W$, is a fundamental parameter of the Standard Model and a sensitive probe of electroweak physics across various energy scales. At low momentum transfer, the Standard Model prediction approaches a well-defined low-energy plateau, providing a target for precision tests of the electroweak theory. At the lowest momentum transfer, atomic parity violation (APV) in cesium provides one of the most precise determinations of the weak mixing angle. Here, we review and update the status of this determination and compare it with other available probes. We then consistently reanalyze low-energy neutrino scattering data and combine the resulting determinations from coherent elastic scattering (CE$ν$NS) and neutrino-electron scattering. The complementary sensitivity of these processes to electroweak couplings enables a neutrino-based determination of the low-energy weak mixing angle, accounting for electroweak radiative corrections and relevant theoretical uncertainties. Our global analysis yields $\sin^2θ_W^{\rm low}(ν\,\text{data}) = 0.233^{+0.007}_{-0.006}$. We assess the consistency and relative impact of the individual neutrino measurements and discuss the prospects for future CE$ν$NS and neutrino-electron scattering experiments to improve the precision of this determination. Our analysis provides an independent test of the Standard Model at low momentum transfer, complementary to that provided by atomic parity violation.

hep-ph↗

arXiv2026

Chaos of Caputo derivative

We study bounded realizations of Caputo differentiation on coefficient Banach spaces of fractional power series. The main contribution is an explicit quantitative analysis of local approximation and periodic reconstruction. We determine the least possible simultaneous error in the initial displacement and the prescribed target. The optimal value is attained, and a minimizing perturbation is given explicitly. We also solve the exact-arrival problem and establish uniqueness of its least-norm solution. These formulas provide computable approximation times and identify the sharp threshold for hypercyclicity, mixing and Devaney chaos. Every periodic point is described by a finite block whose geometric repetition yields exact norm formulas. The resulting approximations attain any prescribed sufficiently large minimal period near any given vector. For distinct positive powers, a simultaneous block construction gives quantitative error estimates and the same sharp threshold for disjoint mixing. Compact embeddings relate the Banach realizations to the Mittag-Leffler-Caputo Fréchet space. They also exhibit dense stable invariant subspaces inside chaotic realizations. The local approximation condition is a norm formulation of classical transitivity. Its quantitative evaluation, together with explicit periodic and simultaneous reconstruction, provides the central results of the study.

math.AP↗

arXiv2026

IndoNutriQA: An Indonesian Clinical Nutrition Question Answering Benchmark

Clinical Question Answering (QA) underpins Clinical Intelligent Decision Support Systems, but progress is severely limited for low-resource languages such as Indonesian by the absence of public domain-specific data. We introduce IndoNutriQA, an expert-curated Indonesian clinical QA benchmark of 911 question-answer pairs built from real clinical-nutrition reports. Rather than a large-scale training corpus, it is positioned as a high-quality evaluation resource: every pair is grounded in a clinically relevant context, enriched with structured metadata (anthropometric assessment, medical diagnosis, document provenance, chunk segmentation). Eight standardised question types following the Nutrition Care Process (NCP), including the Problem, Etiology, Sign and Symptom (PES) diagnosis statement, are answered for every report, which was written by a graduate-level dietetic intern, by one of three nutritionists. Answers are free-form clinical prose rather than extractive spans, and an expert validation study finds 6-10% of reference answers contestable. The dataset supports generative, extractive and retrieval-augmented QA as well as zero- and few-shot LLM evaluation. We report fine-tuned baselines (IndoBERT variants, mT5, RAG) with 5-fold cross-validation, learning curves and bootstrap 95% confidence intervals, and benchmark eight contemporary LLMs zero- and five-shot. We further calibrate our LLM-as-judge rubric against three expert raters (one RD, two nutritionists), finding it human-comparable on factuality and completeness but unreliable on clinical safety, and a human error analysis shows it misses unsupported content that the raters identify. IndoNutriQA is released to foster research in Indonesian clinical NLP and nutritional decision support.

cs.CL↗

arXiv2026

Chordal Construction of Column-Twisted Reed--Solomon Codes

A $[n,k]_q$ Generalized Reed--Solomon (GRS) code can be represented, up to monomial equivalence, by a projective system consisting of $n$ points on a degree $(k-1)$ rational normal curve (RNC) $C_{k-1}$ in PG$(k-1,q)$. We use the term \textit{Column-Twisted Reed--Solomon (CTRS)} codes broadly for $[n,k]_q$ codes whose projective system contains at least $(k+2)$ points on a $C_{k-1}$ of PG$(k-1,q)$. By a chord of $C_{k-1}$, we mean a line which is either a tangent, a real secant, or an imaginary secant of $C_{k-1}$. Roth and Lempel constructed non-GRS MDS $[n,k]_q$ codes by considering projective systems consisting of $(n-1)$ points on $C_{k-1}$ together with a point on a tangent line. More recently, Liu et al. obtained non-GRS $[n, k]_q$ MDS codes by considering projective systems consisting of $(n-2)$ points on $C_{k-1}$ together with a pair of points on a real secant. In the case when $q$ is odd, the length of these codes satisfies $k+4 \leq n \leq (q+3)/2$. In this article, we construct non-GRS $[n,k]_q$ MDS codes by considering projective systems consisting of $(n-2)$ points on $C_{k-1}$ together with a pair of Galois conjugate points on an imaginary secant. For odd $q$, these codes have lengths satisfying $k+4 \le n\le (q+5)/2$, thereby improving both the attainable lengths and dimension ranges of previous TRS and CTRS constructions. In particular, our code attains the length $(q+5)/2$ for every $3\le k\le (q-3)/2$. We use a geometric argument to establish the non-GRS property of CTRS codes for the range $3\le k \le n-4$, while the traditional method of comparison with the Schur square of GRS codes proves the non-GRS property only for the narrower range $3\le k \le n/2$. We also determine the structure of the dual of any CTRS code.

cs.IT↗

arXiv2026

On the Calibration of Isotonic Distributional Regression

Isotonic distributional regression (IDR) has recently been proposed as a non-parametric technique for probabilistic forecasting via the estimation of conditional distributions under order restrictions, based on continuous outcomes from deterministic model outputs. IDR has been widely used and multiple studies report promising performance and well-calibrated forecasts across application domains. We document a peculiar out-of-sample artifact of IDR, where probability integral transform (PIT) values are rational fractions with empirical frequencies resembling Thomae's function, an effect which thus far seems to have been overlooked. This phenomenon is demonstrated empirically using meteorological data and a simulation study. We further provide a theoretical explanation linking the spiking behavior to the discrete structure of the isotonic fits, and discuss how this artifact can be mitigated via smoothing approaches.

stat.ME↗

arXiv2026

A Systematic Comparison of Search Space Complexity and Efficiency for Time-Synchronous End-to-End ASR Models

Search is a central component of Automatic Speech Recognition (ASR) systems and has been deeply investigated for classical ASR modeling based on Hidden Markov Models (HMMs). However, in work on current sequence-to-sequence ASR architectures it is often simplified to a small fixed-size beam search without external Language Model (LM). In this work, we present a comparative analysis of search space complexity and efficiency for Connectionist Temporal Classification (CTC) and neural transducer models under different pruning strategies and LM configurations. We show that these end-to-end (E2E) models work with a small search space most of the time but exhibit large temporary peaks in hypothesis count during periods of uncertainty. Score-based pruning dynamically adapts the search to model uncertainty, leading to a significantly lower Real-Time Factor (RTF). Our results highlight the limitations of search with low fixed-size beam pruning and provide practical guidelines for efficient search in E2E ASR.

cs.CL↗

arXiv2026

Can Entanglement-Induced Feature-Map Designs Improve Projected Quantum Kernels?

Projected quantum kernels (PQKs) have emerged as a notable approach to circumvent the hardness of machine learning tasks arising from the exponential dimensionality of the quantum Hilbert space. However, recent PQK studies often rely heavily on extensive classical hyperparameter tuning of the radial basis function (RBF) kernel parameter and the support vector machine regularization parameter. The extensive tuning can mask the true representational power of the underlying PQKs induced by quantum feature maps, which has not been explored in detail. Thus, this work aims to expose the structural capabilities of PQKs by isolating and evaluating their native inductive bias through comparisons between untuned and tuned PQKs against the RBF baseline. Furthermore, we propose novel quantum feature maps that leverage two-qubit entanglement to capture multivariate correlations in IoT data. The results show that extensive tuning can lead to competitive performance architectures, while our proposed entanglement topologies exhibit a significantly stronger native inductive bias. This reveals that superior quantum architectural design can yield structurally better PQKs with improvements arising from quantum-mechanical properties rather than from classical hyperparameter tuning.

quant-ph↗

arXiv2026

A Polynomial-Time Algorithm for $k$-Path Vertex Cover Reconfiguration on Trees under Token Sliding

A $k$-path vertex cover ($k$-PVC) of a graph is a set of vertices meeting every path on $k$ vertices. In Token Sliding, one token occupies each vertex of a cover; a move slides one token along an edge to an unoccupied vertex, preserving the cover property. We study whether two covers of a tree are joined by such moves. The case $k=2$ admits a linear-time decision algorithm. For every integer $k\geq2$, we give an $O(kn^2)$-time decision algorithm on trees of order $n$, with $k$ part of the input. Two covers are reachable precisely when their rigid tokens, which never move, occupy the same set and every component remaining after their deletion has the same token count. The proof transforms configurations of equal size without rigid tokens into a canonical configuration built on properly rooted subtrees, whose paths on $k$ vertices pass through their roots. A rooted-subtree recurrence identifies movable candidate tokens. We also give a direct recursive construction between the supplied endpoints, returning at most $8n^2\,3^{\lceil n/2\rceil}$ slides in $O(n^{10}3^{n/2})$ time. ChatGPT 6 Pro and Claude Fable 5.1 were used to assist with developing and reviewing mathematical arguments and drafting and revising the paper. The author takes full responsibility for the correctness and content of the paper.

cs.DS↗

arXiv2026

A New Minimax Theorem for a Class of $C^1$-Functionals

We establish a new abstract minimax theorem for obtaining ground-state critical points of a class of $C^{1}$-functionals. The central feature of this class is that the associated Nehari set is not necessarily a differentiable manifold, but is homeomorphic to a (possibly non-complete) submanifold of the unit sphere. This occurs for functionals whose fibering maps $t \mapsto I(tu)$ possess a unique global maximum point only when $u$ belongs to an open cone in the underlying Banach space. A lower semicontinuous boundary barrier, which may be finite, controls minimizing sequences near the boundary of the spherical cone. As a consequence, we provide a general minimax characterization of the ground-state energy level. Elliptic applications complement existing results and include superlinear and quasilinear problems with finite barriers, including thresholds depending on the profile of a first eigenfunction and its gradient.

math.AP↗

arXiv2026

Kempe Reachability with $k\geq 3$ Colors Is $\mathsf{PSPACE}$-Complete on Claw-Free Graphs

A \emph{proper vertex coloring} assigns colors to vertices so that adjacent vertices have distinct colors. A \emph{Kempe change} in a proper vertex coloring exchanges two colors on one component of the subgraph induced by the vertices of those colors. For a fixed palette of $k$ colors, \textsc{Kempe Reachability} asks whether two given proper vertex colorings of the same graph are connected by a sequence of Kempe changes. This problem is known to be $\mathsf{PSPACE}$-complete for every fixed $k\geq 3$. A graph is \emph{claw-free} if no vertex has three pairwise nonadjacent neighbors. The \emph{line graph} of a graph has one vertex for each edge, with two vertices adjacent exactly when the corresponding edges share an end. Line graphs are claw-free, and their Kempe changes correspond to \emph{edge-Kempe changes} in the original graph, which exchange two colors on one component of the subgraph formed by the edges of those colors. A claw-free graph with a proper $k$-coloring has maximum degree at most $2k-2$, whereas for $k\geq 4$ all proper $k$-colorings of a graph of maximum degree at most $k$ are connected by Kempe changes. We show that, for every fixed $k\geq 3$, \textsc{Kempe Reachability} with $k$ colors is $\mathsf{PSPACE}$-complete even on line graphs of connected simple $k$-regular graphs, and hence even on connected $(2k-2)$-regular claw-free graphs. Equivalently, deciding whether two proper $k$-edge-colorings are connected by edge-Kempe changes is $\mathsf{PSPACE}$-complete even on connected simple $k$-regular graphs. ChatGPT 6 Pro and Claude Fable 5.1 were used to assist with developing and reviewing mathematical arguments and drafting and revising the paper. The author takes full responsibility for the correctness and content of the paper.

cs.DS↗

arXiv2026

Deep ReLU Networks Can Fail the Best Approximation Property for Continuous Target Functions

We construct a continuous function on $[-1,1]^2$ for which the infimum of the $L^2$-approximation error over the class of ReLU networks with two hidden layers and architecture $(2,2,1,1)$ is not attained. This counterexample shows that deep ReLU networks do not satisfy the best approximation property in general, even for continuous target functions. Our findings contrast with existing results for shallow neural networks, where ReLU is one of the few activation functions that guarantee the existence of global minima in typical regression tasks. The proof is based on the fact that the breaklines for neurons in the second hidden layer can bend, which breaks the symmetry arguments used in the one-hidden-layer case.

cs.LG↗

arXiv2026

Log blow-ups and global resolutions in rigid geometry

In this article, we study log blow-ups in the setting of log adic spaces. As in the theory of log schemes, we prove the existence of global resolutions of toric singularities for fs log adic spaces log smooth over a $p$-adic field, and the acyclicity of certain sheaves under log blow-ups. One new feature of (log) rigid analytic varieties is their integral structure sheaf: we prove that it is also almost acyclic under log blow-ups in the Kummer étale topology. We also supply some foundational results on log adic spaces.

math.AG↗

arXiv2026

Notation3: Graph Terms for RDF

Notation3 Logic was introduced as an extension of RDF allowing the user to express rules on top of triples and to make statements about graphs. The original proposal of the logic only came with an informal specification of its semantics which has been refined later on. While this refinement clarified the meaning of rules and implicitly quantified variables, it left the meaning of graphs used as terms - so-called graph terms - open. In this paper we aim to close this gap. We discuss in detail, how graph terms are used in Notation3, which formal requirements they need to meet, and provide examples to illustrate the difficulties when defining their semantics. We then introduce an abstract syntax for the logic and define its semantics in two steps: similarly to RDF's simple interpretations, we define interpretations and basic entailment for Notation3 which covers plain RDF triples but also triples containing graph terms. N3-entailment is then an extension of basic entailment which assigns meaning to the different special predicates of the logic like for example the implication symbol. N3-entailment is defined in a way that it can be extended whenever a new predicate is added to the logic. As Notation3 Logic is currently under development, we expect many predicates to be added. Our research provides and important step towards the full standardisation of the logic.

cs.LO↗

arXiv2026

Radial $Φ^4$ models in supercritical regimes

We consider the $Φ^4_d$ measure under radial symmetry on the unit ball, formally given by $$dρ(u) = \frac 1 Z \exp\Big( - \frac 14 \int_{B_1} |u|^4 dx - \frac 12 \int_{B_1} |\nabla u|^2 dx\Big) d u, $$ where $u$ is restricted to radially symmetric functions with 0 boundary conditions. We prove that for every dimension $d$, there exists such a measure, which is concentrated on $L^p(B_1)$ for every $p < \frac{2d}{d-2}$ (for every $p < \infty$ if $d \le 2$). Furthermore, we show that these measures are not Gaussian, and when $d \ge 4$, they are singular with respect to the underlying Gaussian measure. We achieve this result by first defining the measure $ρ^+_δ[λ]$ on the shell $\{δ\le |x| \le 1\}$, $0 < δ< 1$, with a boundary condition on the sphere of radius $δ$ of the form $u|_{\{|x| = δ\}} = λ$. Then we prove that this measure satisfies a variational formula, and use it to show moment bounds which are uniform in the boundary value $λ$. A crucial ingredient in this argument is the fact that every solution of the elliptic equation $-Δu + u^3 = 0$ on the annulus $\{ δ\le |x| \le 1 \}$ satisfies uniform bounds inside the domain, independently of the boundary conditions.

math.AP↗

arXiv2026

Rank-One Loss Maximizes the Spectral Response Strength of Passive Full-Order Exceptional Points

We consider finite-dimensional non-Hermitian systems in which all modes coalesce at a single exceptional point. For a rank-one anti-Hermitian contribution, the spectral response strength is computed exactly. For passive systems, we then derive a sharp upper bound at fixed exceptional-point decay rate and show that it is reached only when the decay operator has rank one, corresponding to a single independent dissipative direction. This establishes rank-one loss as the optimal configuration for enhancing the response of a full-order exceptional point. The bound holds for arbitrary order and improves on earlier passive estimates beyond second order. Two third-order trimers illustrate the result: a rank-one-loss system saturates the bound, whereas a passive rank-two-loss realization remains below it. The result turns dissipation into a design resource: concentrating the loss into a single effective dissipative direction maximizes the highest-order spectral response of a passive full-order exceptional-point device.

quant-ph↗

arXiv2026

Monodromy Defects of 3D Wilson-Fisher Criticality on the Fuzzy Sphere

Monodromy (twist) line defects arise as the boundaries of topological symmetry surfaces, which are among the simplest non-trivial conformal defects with direct realizations as magnetic vortex in quantum magnets, as Wilson and t Hooft lines of gauge theories, and as the replica twist operators in quantum information theory. However, their interacting dynamics remains difficult to characterize non-perturbatively. Here we design a way to realize the monodromy boundary conditions in the fuzzy-sphere regularization by threading a symmetry-selective Aharonov-Bohm flux through the two poles of the sphere. We apply this construction to the $\mathbb{Z}_2$ twist of the 3D Ising conformal field theory (CFT), $π$-twist of the 3D O(2) CFT and three inequivalent monodromies of O(3) (centre twist, z-axis $π$-twist and the reflection). For each defect, we extract the low-lying defect spectrum together with bulk-to-defect and defect-defect operator product expansion coefficients, which characterize the operators living on the defect line, their mutual interactions, and how they couple to the surrounding critical bulk. Among the low-lying defect primaries resolved in our spectra, we find no relevant scalar perturbation that preserves all the symmetries of the corresponding defect. The relevant deformations identified in our calculations break at least one preserved symmetry, providing evidence that these monodromy defects are stable against symmetry-preserving relevant perturbations. These results establish a systematic set of non-perturbative conformal data for monodromy defects beyond the Ising twist. Our construction therefore turns the symmetry flux into a tunable knob of the fuzzy-sphere regularization, opening a route to exploring the response of critical matter to distinct defects.

hep-th↗