Tootfinder

Peculiarities of quantum field theory in the presence of a wormhole
Mikhail N. Smolyakov
https://arxiv.org/abs/2506.21256 https://arx…

Peculiarities of quantum field theory in the presence of a wormhole
In this paper, quantum theory of a real massive scalar field in the background of a traversable wormhole is examined. The wormhole is supposed to connect two different universes, as a particular example the simplest Ellis wormhole is considered. It is shown that the resulting theory possesses a doubling of quantum states parameterized by the same value of asymptotic momentum, two different sets of such degenerate states are localized in different universes. This is a consequence of the topologi…

This https://arxiv.org/abs/2505.22371 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_sta…

Adaptive tail index estimation: minimal assumptions and non-asymptotic guarantees
A notoriously difficult challenge in extreme value theory is the choice of the number $k\ll n$, where $n$ is the total sample size, of extreme data points to consider for inference of tail quantities. Existing theoretical guarantees for adaptive methods typically require second-order assumptions or von Mises assumptions that are difficult to verify and often come with tuning parameters that are challenging to calibrate. This paper revisits the problem of adaptive selection of $k$ for the Hill…

Vacuum energy in effective field theory of general relativity
E. Epelbaum, J. Gegelia, Ulf-G. Mei{\ss}ner
https://arxiv.org/abs/2506.19182 https://

Vacuum energy in effective field theory of general relativity
It is shown to all orders of perturbation theory that in the effective field theory of general relativity the condition of vanishing of the vacuum energy leads to the same value of the cosmological constant, viewed as a parameter of the effective Lagrangian, as obtained by demanding the consistency of the effective field theory in Minkowski background. The resulting effective action is characterized by the cosmological constant term that vanishes exactly.

Central limit theory for Peaks-over-Threshold partial sums of long memory linear time series
Ioan Scheffel, Marco Oesting, Gilles Stupfler
https://arxiv.org/abs/2506.20789

Central limit theory for Peaks-over-Threshold partial sums of long memory linear time series
Over the last 30 years, extensive work has been devoted to developing central limit theory for partial sums of subordinated long memory linear time series. A much less studied problem, motivated by questions that are ubiquitous in extreme value theory, is the asymptotic behavior of such partial sums when the subordination mechanism has a threshold depending on sample size, so as to focus on the right tail of the time series. This article substantially extends longstanding asymptotic techniques …

Adaptive tail index estimation: minimal assumptions and non-asymptotic guarantees
Johannes Lederer, Anne Sabourin, Mahsa Taheri
https://arxiv.org/abs/2505.22371

Adaptive tail index estimation: minimal assumptions and non-asymptotic guarantees
A notoriously difficult challenge in extreme value theory is the choice of the number $k\ll n$, where $n$ is the total sample size, of extreme data points to consider for inference of tail quantities. Existing theoretical guarantees for adaptive methods typically require second-order assumptions or von Mises assumptions that are difficult to verify and often come with tuning parameters that are challenging to calibrate. This paper revisits the problem of adaptive selection of $k$ for the Hill…

A General Theory of Risk Sharing
Vasily Melnikov
https://arxiv.org/abs/2505.19276 https://arxiv.org/pdf/2505.19276

A General Theory of Risk Sharing
We introduce a new paradigm for risk sharing that generalizes earlier models based on discrete agents and extends them to allow for sharing risk within a continuum of agents. Agents are represented by points of a measure space and have potentially heterogeneous risk preferences modeled by risk measures. The existence of risk minimizing allocations is proved when constrained to satisfy economically convincing conditions. In the unconstrained case, we derive the dual representation of the value f…

This https://arxiv.org/abs/2311.17270 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_qfi…

Exponential Utility Maximization in a Continuous Time Gaussian Framework
In this work we study the continuous time exponential utility maximization problem in the framework of an investor who is informed about the price changes with a delay. This leads to a non-Markovian stochastic control problem. In the case where the risky asset is given by a Gaussian process (with some additional properties) we establish a solution for the optimal control and the corresponding value. Our approach is purely probabilistic and is based on the theory for Radon-Nikodym derivatives of…

Moment-like maps and real algebraic functions with prescribed preimages
Naoki Kitazawa
https://arxiv.org/abs/2506.17791 https://arxiv…

Moment-like maps and real algebraic functions with prescribed preimages
We discuss a problem on singularity theory of differentiable (smooth) or real algebraic maps which is different from knowing existence and has been difficult: constructing explcit real algebraic functions. We discuss construction of real algebraic functions with exactly one singular value, the singular points being of definite type, and prescribed preimages of single points. We discuss generalizations of the canonical projection of the unit sphere around the pole and the Morse-Bott functions …

Multivariate Discrete Generalized Pareto Distributions: Theory, Simulation, and Applications to Dry spells
Samira Aka, Marie Kratz, Philippe Naveau
https://arxiv.org/abs/2506.19361

Multivariate Discrete Generalized Pareto Distributions: Theory, Simulation, and Applications to Dry spells
This article extends the multivariate extreme value theory (MEVT) to discrete settings, focusing on the generalized Pareto distribution (GPD) as a foundational tool. The purpose of the study is to enhance the understanding of extreme discrete count data representation, particularly for discrete exceedances over thresholds, defining and using multivariate discrete Pareto distributions (MDGPD). Through theoretical results and illustrative examples, we outline the construction and properties of MD…

A new infinite-dimensional Linking theorem with application to a system of coupled Poisson equations
Ablanvi Songo, Fabrice Colin
https://arxiv.org/abs/2506.17563

A new infinite-dimensional Linking theorem with application to a system of coupled Poisson equations
Using the minimax technique from the critical point theory, which consists in constructing or transforming a suitable class of applications such that a critical value $c$ of a functional $f$ can be characterized as a minimax value over this class, we establish a new natural infinite-dimensional linking theorem for strongly indefinite functionals by using the $τ-$topology of Kryszewski and Szulkin. Our result is a generalization of the classical linking theorem \cite[Theorem 2.21]{Wi}. As an ap…

A theory of Lending Protocols in DeFi
Massimo Bartoletti, Enrico Lipparini
https://arxiv.org/abs/2506.15295 https://arxiv.org/pdf/250…

A theory of Lending Protocols in DeFi
Lending protocols are one of the main applications of Decentralized Finance (DeFi), enabling crypto-assets loan markets with a total value estimated in the tens of billions of dollars. Unlike traditional lending systems, these protocols operate without relying on trusted authorities or off-chain enforcement mechanisms. To achieve key economic goals such as stability of the loan market, they devise instead trustless on-chain mechanisms, such as rewarding liquidators who repay the loans of under-…

The perfect spinfluid
Nick Abboud, Lorenzo Gavassino, Rajeev Singh, Enrico Speranza
https://arxiv.org/abs/2506.19786 https://arxiv.or…

The perfect spinfluid
We present a new formulation of non-dissipative relativistic spin hydrodynamics that incorporates spin degrees of freedom into the divergence-type theory framework. Due to the divergence-type structure, it is straightforward to enforce non-linear causality and symmetric hyperbolicity of the equations of motion, ensuring local well-posedness of the initial-value problem and stability of the theory. Furthermore, in a specific realization based on spin kinetic theory, we prove that the equations o…

This https://arxiv.org/abs/2308.13717 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_qfi…

Portfolios Generated by Contingent Claim Functions, with Applications to Option Pricing
This paper presents a synthesis of the theories of portfolio generating functions and option pricing. The theory of portfolio generation is extended to measure the value of portfolios generated by positive C^{2,1} functions of asset prices X_1,... , X_n directly, rather than with respect to a numeraire portfolio. If a portfolio generating function satisfies a specific partial differential equation, then the value of the portfolio generated by that function will replicate the value of the functi…

Fully Self-Consistent Semiclassical Gravity
R. Muci\~no, E. Okon, D. Sudarsky, M. Wiedemann
https://arxiv.org/abs/2506.17149 https://…

Fully Self-Consistent Semiclassical Gravity
A theory of quantum gravity consists of a gravitational framework which, unlike general relativity, takes into account the quantum character of matter. In spite of impressive advances, no fully satisfactory, self-consistent and empirically viable theory with those characteristics has ever been constructed. A successful semiclassical gravity model, in which the classical Einstein tensor couples to the expectation value of the energy-momentum tensor of quantum matter fields, would, at the very le…

A Unified Theory of Compositionality, Modularity, and Interpretability in Markov Decision Processes
Thomas J. Ringstrom, Paul R. Schrater
https://arxiv.org/abs/2506.09499

A Unified Theory of Compositionality, Modularity, and Interpretability in Markov Decision Processes
We introduce Option Kernel Bellman Equations (OKBEs) for a new reward-free Markov Decision Process. Rather than a value function, OKBEs directly construct and optimize a predictive map called a state-time option kernel (STOK) to maximize the probability of completing a goal while avoiding constraint violations. STOKs are compositional, modular, and interpretable initiation-to-termination transition kernels for policies in the Options Framework of Reinforcement Learning. This means: 1) STOKs can…

Scattering theory on Riemann surfaces I: Schiffer operators, cohomology, and index theorems
Eric Schippers, Wolfgang Staubach
https://arxiv.org/abs/2506.08160

Scattering theory on Riemann surfaces I: Schiffer operators, cohomology, and index theorems
We consider a compact Riemann surface $\mathscr{R}$ with a complex of non-intersecting Jordan curves, whose complement is a pair of Riemann surfaces with boundary, each of which may be possibly disconnected. We investigate conformally invariant integral operators of Schiffer, which act on $L^{2}$ anti-holomorphic one-forms on one of these surfaces with boundary and produce holomorphic one-forms on the disjoint union. These operators arise in potential theory, boundary value problems, approximat…

On a novel probabilistic Sampling Kantorovich operators and their application
Digvijay Singh, Rahul Shukla, Karunesh Kumar Singh
https://arxiv.org/abs/2506.12053

On a novel probabilistic Sampling Kantorovich operators and their application
This article starts with the fundamental theory of stochastic type convergence and the significance of uniform integrability in the context of expectation value. A novel probabilistic sampling kantorovich (PSK-operators) is established with the help of classical sampling operators (SK-operators). We establish the proof of the fundamental theorem of approximation and a lemma corresponding to the PSK- operators. Moreover, some examples are illustrated not only in numerical form but also in a deta…

Enterprise value, economic and policy uncertainties: the case of US air carriers
Bahram Adrangi, Arjun Chatrath, Madhuparna Kolay, Kambiz Raffiee
https://arxiv.org/abs/2506.07766 …

Enterprise value, economic and policy uncertainties: the case of US air carriers
The enterprise value (EV) is a crucial metric in company valuation as it encompasses not only equity but also assets and liabilities, offering a comprehensive measure of total value, especially for companies with diverse capital structures. The relationship between economic uncertainty and firm value is rooted in economic theory, with early studies dating back to Sandmo's work in 1971 and further elaborated upon by John Kenneth Galbraith in 1977. Subsequent significant events have underscored t…

Improving elliptic curve rank classification using multi-value and learned Mestre-Nagao sums
Zvonimir Bujanovi\'c, Matija Kazalicki, Domagoj Vlah
https://arxiv.org/abs/2506.07967

Improving elliptic curve rank classification using multi-value and learned Mestre-Nagao sums
Determining the rank of an elliptic curve E/Q remains a central challenge in number theory. Heuristics such as Mestre--Nagao sums are widely used to estimate ranks, but there is considerable room for improving their predictive power. This paper introduces two novel methods for enhancing rank classification using Mestre--Nagao sums. First, we propose a ``multi-value'' approach that simultaneously uses two distinct sums, S_0 and S_5, evaluated over multiple ranges. This multi-sum perspective sign…

This https://arxiv.org/abs/2505.14767 has been replaced.
initial toot: https://mastoxiv.page/@arX…

Ordering the topological order in the fractional quantum Hall effect
We discuss the possible topological order/topological quantum field theory of different quantum Hall systems. Given the value of the Hall conductivity, we constrain the global symmetry of the low-energy theory and its anomaly. Specifically, the one-form global symmetry and its anomaly are presented as the organizing principle of these systems. This information is powerful enough to lead to a unique minimal topological order (or a small number of minimal topological orders). Almost all of the kn…

This https://arxiv.org/abs/2502.17982 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Kinetic variable-sample methods for stochastic optimization problems
We discuss kinetic-based particle optimization methods and variable-sample strategies for problems where the cost function represents the expected value of a random mapping. Kinetic-based optimization methods rely on a consensus mechanism targeting the global minimizer, and they exploit tools of kinetic theory to establish a rigorous framework for proving convergence to that minimizer. Variable-sample strategies replace the expected value by an approximation at each iteration of the optimizatio…

This https://arxiv.org/abs/2505.24171 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_eco…

A note on the diversity Owen values
Béal et al. (Int J Game Theory 54, 2025) introduce the Diversity Owen value for TU-games with diversity constraints, and provide axiomatic characterizations using the axioms of fairness and balanced contributions. However, there exist logical flaws in the proofs of the uniqueness of these characterizations. In this note we provides the corrected proofs of the characterizations by introducing the null player for diversity games axiom. Also, we establish two alternative characterizations of the …

Nuclear $\beta$-decay half-lives within the subtracted second random-phase approximation
Danilo Gambacurta, Marcella Grasso
https://arxiv.org/abs/2506.18849

Nuclear $β$-decay half-lives within the subtracted second random-phase approximation
We employ, within the framework of Skyrme energy-density functional theory, the subtracted second random-phase approximation, recently developed for charge-exchange excitations, to compute $β$-decay half-lives in four nuclei, $^{24}$O, $^{34}$Si, $^{78}$Ni, and $^{132}$Sn. Following our recent results on the description of the Gamow-Teller strength, we proceed coherently in the present work by computing $β$-decay half-lives using the bare value of the axial-vector coupling constant $g_A$. Hal…

Scattering theory on Riemann surfaces II: The scattering matrix and generalized period mappings
Eric Schippers, Wolfgang Staubach
https://arxiv.org/abs/2506.08166

Scattering theory on Riemann surfaces II: The scattering matrix and generalized period mappings
We construct a scattering theory for harmonic one-forms on Riemann surfaces, obtained from boundary value problems involving systems of curves and the jump problem. We obtain an explicit expression for the scattering matrix in terms of integral operators which we call Schiffer operators, and show that the matrix is unitary. We also obtain a general association of positive polarizing Lagrangian spaces to bordered Riemann surfaces, which unifies the classical polarizations for compact surfaces of…

This https://arxiv.org/abs/2504.06481 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

Statistical Physics of the Polarised IKKT Matrix Model
The polarised IKKT matrix model is the worldpoint theory of $N$ D-instantons in a background three-form flux of magnitude $Ω$, and promises to be a highly tractable model of holography. The matrix integral can be viewed as a statistical physics partition function with inverse temperature $Ω^4$. At large $Ω$ the model is dominated by a matrix configuration corresponding to a 'polarised' spherical D1-brane. We show that at a critical value of $Ω^2 N$ the model undergoes a first order phase tr…

This https://arxiv.org/abs/2110.06506 has been replaced.
link: https://scholar.google.com/scholar?q=a

Network analysis using Forman curvature and Shapley values on hypergraphs
In recent years, network models have become more complex with the development of big data. Therefore, more advanced network analysis is required. In this paper, we introduce a new quantitative measure named combinatorial evaluation, which combines the discrete geometry concept of Forman Ricci curvature and the game theory concept of the Shapley value. We elucidated the characteristics of combinatorial evaluation by proving several properties of this indicator. Furthermore, we demonstrated the u…

This https://arxiv.org/abs/2412.17556 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Bekenstein bounds in maximally symmetric nonlinear electrodynamics
We explore dynamical features of the maximally symmetric nonlinear extension of classical electromagnetism, recently proposed in the literature as ``ModMax'' electrodynamics. This family of theories is the only one that preserves all the symmetries of Maxwell's theory, having applications in the study of regular black hole solutions and supersymmetry. The purpose of this article is three-fold. Firstly, we study the initial-value problem of ModMax and show, by means of a simple geometric criteri…

This https://arxiv.org/abs/2310.00407 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

On the limit theory of mean field optimal stopping with non-Markov dynamics and common noise
This paper focuses on a mean-field optimal stopping problem with non-Markov dynamics and common noise, inspired by Talbi, Touzi, and Zhang \cite{TalbiTouziZhang1,TalbiTouziZhang3}. The goal is to establish the limit theory and demonstrate the equivalence of the value functions between weak and strong formulations. The difference between the strong and weak formulations lies in the source of randomness determining the stopping time on a canonical space. In the strong formulation, the randomness …

A note on the diversity Owen values
Songtao He, Erfang Shan, Xinyu Sun
https://arxiv.org/abs/2505.24171 https://arxiv.org/pdf/2505.24…

A note on the diversity Owen values
Béal et al. (Int J Game Theory 54, 2025) introduce the Diversity Owen value for TU-games with diversity constraints, and provide axiomatic characterizations using the axioms of fairness and balanced contributions. However, there exist logical flaws in the proofs of the uniqueness of these characterizations. In this note we provides the corrected proofs of the characterizations by introducing the null player for diversity games axiom. Also, we establish two alternative characterizations of the …

This https://arxiv.org/abs/2505.20111 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Preference Disaggregation Analysis with Criteria Selection in a Regularization Framework
Limited by cognitive abilities, decision-makers (DMs) may struggle to evaluate decision alternatives based on all criteria in multiple criteria decision-making problems. This paper proposes an embedded criteria selection method derived from preference disaggregation technique and regularization theory. The method aims to infer the criteria and value functions used by the DM to evaluate decision alternatives. It measures the quality of criteria subsets by investigating both the empirical error (…

From Explicit Diffeomorphism Breaking to Spontaneous Unimodularization
Yuri Bonder, Johas D. Morales
https://arxiv.org/abs/2506.12499 https://

From Explicit Diffeomorphism Breaking to Spontaneous Unimodularization
This contribution investigates modifications of General Relativity that allow or mimic energy nonconservation. We focus on Unimodular Gravity (UG), a theory that explicitly breaks diffeomorphism invariance, and show that it can lead to particle acceleration, opening the door to experimental constraints. We also argue that UG admits a well-posed initial value formulation, despite the presence of nondynamical structures. Finally, we introduce a simple model that spontaneously mimics UG, but in wh…

This https://arxiv.org/abs/2505.06369 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

Yang-Lee Quantum Criticality in Various Dimensions
The Yang-Lee universality class arises when imaginary magnetic field is tuned to its critical value in the paramagnetic phase of the $d<6$ Ising model. In $d=2$, this non-unitary Conformal Field Theory (CFT) is exactly solvable via the $M(2,5)$ minimal model. As found long ago by von Gehlen using Exact Diagonalization, the corresponding real-time, quantum critical behavior arises in the periodic Ising spin chain when the imaginary longitudinal magnetic field is tuned to its critical value from …