Papers

  • Nonparametric Goodness-of-fit Testing under Covariate Shift

    This paper develops procedures for nonparametric goodness-of-fit testing under covariate shift, where labelled data are drawn from a source population but goodness-of-fit is evaluated for a target population. The distribution mismatch is quantified by either a bounded moment condition or a sub-exponential tail condition on the target-to-source density ratio. Our …

  • A Counterexample to Fourier Alignment in Single-Neuron Modular Addition

    We give a negative solution to MAIS-O60. We first construct an example in which an initially active ReLU neuron becomes completely inactive in finite time and thereafter remains frozen at a limit whose Fourier energy is equally distributed among all nonzero real frequency classes. The counterexample holds on an open …

  • Monsoon Mayhem to Market Waves: Forecasting Fisheries Resilience in Sri Lanka

    Sri Lanka's fisheries sector is important for jobs and food supply. Between 2019 and 2025, it faced several major problems at the same time, and how these events together affected fish production and prices is still not well understood. This study develops a framework to connect weather changes, major disruption …

  • Polynomial Time Quantum Approximation Schemes for Constrained Optimisation

    When does a noisy quantum sampler yield an end-to-end polynomial-time optimization algorithm with performance guarantees? Building on finite-depth and finite-shot guarantees for Constraint-Enhanced QAOA, we show that inverse-polynomial ideal probability on the optimal set, together with independent sampling, polynomial-time feasibility repair, and scoring, produces an exact-hit fully polynomial randomized approximation …

  • Economic Power in International Trade

    Economic power is a country's capacity to harm another more than itself by withdrawing from a trading relationship. This paper develops a short-run model of trade disruptions to measure that power through counterfactual experiments. Sanctioned buyers and sellers relocate some of the barred flows onto alternate trade partners. Every producer, …

  • Characterizing Robustness in Nonlinear Optimal Control: From Stability to Optimality

    In nonlinear optimal control, uncertainties in system dynamics may affect not only closed-loop stability but also the achieved optimality properties of the resulting solutions. This paper develops a systematic robustness analysis for nonlinear optimal control beyond the conventional focus on stability in robust control theory. First, we demonstrate that the …

  • EqDeepRx: Learning a Scalable and Interference Mitigating MIMO Receiver

    While machine learning (ML)-based receiver algorithms have received a great deal of attention in the recent literature, they often suffer from poor scaling with increasing spatial multiplexing order and lack of explainability and generalization. This paper presents EqDeepRx, a practical deep-learning-aided multiple-input multiple-output (MIMO) receiver, which is built by augmenting …

  • Two-Dimensional Billiards Are Turing Complete

    We show that two-dimensional billiard systems can simulate universal Turing machines. Billiards serve as idealized models of particle motion with elastic reflections and arise naturally as limits of smooth Hamiltonian systems under steep confining potentials. By invoking the undecidability of the halting problem, originally established by Turing, our results show …

  • A note on conditional PAC-efficient reasoning in large language model routing

    We study distribution-free risk control for model routing, motivated by large language model reasoning. We formalize pointwise conditional efficiency under a probably approximately correct guarantee and show that it forces a nearly impossible router: at almost every input where the fast model exceeds the target loss, the algorithm must route …