Negative / Null Result ReportOpen accessComputer Science
Kenichi Konishi · 2023 · arXiv
We comment on the so-called negative-result experiments (also known as null measurements, interaction-free measurements, and so on) in quantum mechanics (QM), in the light of the new general understanding of the quantum-measurement processes, proposed recently. All experiments of this kind (null-measurements) can be understood as improper measurements with an intentionally biased detector set up, which introduces exclusion or selection of certain events. The prediction on the state of a microscopic system under study based on a null measurement, is sometimes dramatically described as ``wave-fu
Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Taylor Knipe, Josue Ortega · 2025 · arXiv
The celebrated Efficiency-Adjusted Deferred Acceptance mechanism (EADA) improves the efficiency of the DA algorithm via consented priority violations. Notwithstanding its many merits, we show that EADA can improve only two students when an alternative mechanism that Pareto-dominates DA could benefit all but one student. This shortfall in the number of students improved is not exclusive of EADA but extends to all setwise minimally unstable mechanisms, i.e. those that generate a set of blocking pairs that is never a strict superset of that of another mechanism. The incompatibility between number
Negative / Null Result ReportOpen accessComputer Science
Fabrizio Ottati, Giovanna Turvani, Marco Vacca et al. · 2023 · arXiv
The speed of modern digital systems is severely limited by memory latency (the ``Memory Wall'' problem). Data exchange between Logic and Memory is also responsible for a large part of the system energy consumption. Logic--In--Memory (LiM) represents an attractive solution to this problem. By performing part of the computations directly inside the memory the system speed can be improved while reducing its energy consumption. LiM solutions that offer the major boost in performance are based on the modification of the memory cell. However, what is the cost of such modifications? How do these impa
Negative / Null Result ReportOpen accessComputer Science
Mykolas Sveistrys, Richard Kunert · 2025 · arXiv
Retrieval-Augmented Generation (RAG) has been used in question answering (QA) systems to improve performance when relevant information is in one (single-hop) or multiple (multi-hop) passages. However, many real life scenarios (e.g. dealing with financial, legal, medical reports) require checking all documents for relevant information without a clear stopping condition. We term these pluri-hop questions, and formalize them by 3 conditions - recall sensitivity, exhaustiveness, and exactness. To study this setting, we introduce PluriHopWIND, a multilingual diagnostic benchmark of 48 pluri-hop que
Negative / Null Result ReportOpen accessPhysics
Asif Manzoor Hasan, Johan Larsson, Sergio Pirozzoli et al. · 2023 · arXiv
A transformation that relates a compressible wall-bounded turbulent flow with non-uniform fluid properties to an equivalent incompressible flow with uniform fluid properties is derived and validated. The transformation accounts for both variable-property and intrinsic compressibility effects, the latter being the key improvement over the current state-of-the-art. The importance of intrinsic compressibility effects contradicts the renowned Morkovin's hypothesis.
Negative / Null Result ReportOpen accessComputer Science
Xu Ma, Jiajie Zhang, Fujing Xie et al. · 2025 · arXiv
Global localization is essential for autonomous robotics, especially in indoor environments where the GPS signal is denied. We propose a novel WiFi-based localization framework that leverages ubiquitous wireless infrastructure and the OpenStreetMap Area Graph (osmAG) for large-scale indoor environments. Our approach integrates signal propagation modeling with osmAG's geometric and topological priors. In the offline phase, an iterative optimization algorithm localizes WiFi Access Points (APs) by modeling wall attenuation, achieving a mean localization error of 3.79 m (35.3\% improvement over tr
Negative / Null Result ReportOpen accessMathematics
John Rozmarynowycz, Seungki Kim · 2023 · arXiv
We report the finding of the new upper bound on the lowest positive integer $x$ for which the Mertens conjecture \begin{equation*} \left| \sum_{1 \leq n \leq x} μ(n) \right| < \sqrt{x} \end{equation*} fails to hold: $x < \exp(1.017 \times 10^{29})$, an improvement over previously known $\exp(1.59 \times 10^{40})$ due to Kotnik and te Riele [7].
Negative / Null Result ReportOpen accessMathematics
D. R. Heath-Brown · 2026 · arXiv
We show that there are $O(B^{3/5-3/1555+\ep})$ triples $(x,y,z)$ of square-full integesr up to $B$ satisfying the equation $x+y=z$ for any fixed $\ep>0$. This is the first improvement over the `easy' exponent $3/5$, given by Browning and Van Valckenborgh. One new tool is a strong uniform bound for the counting function for equations $aX^3+bY^3=cZ^3$.
Negative / Null Result Report
David Mills · 2017 · Veterinary Evidence
Therapy and prognosis are entailed by the diagnosis: the holistic success of the EBVM approach therefore firmly and critically rests on diagnostic accuracy.Unfortunately, medical professionals do not appear to be very accurate with…
View details →DOI: 10.18849/ve.v2i3.147 Negative / Null Result Report
Henry Lam · 2025 · Management Science
When the underlying probability distribution in a stochastic optimization is observed only through data, various data-driven formulations have been studied to obtain approximate optimal solutions. We show that no such formulations can, in…
View details →DOI: 10.1287/mnsc.2024.04482 Negative / Null Result Report
Timothy Daniel Allerton, Stefany D. Primeaux · 2013 · The FASEB Journal
The propensity for some individuals to develop obesity has been linked to intake of a high fat diet (HFD) and physical inactivity. However, some individuals resist obesity through improved energy sensing and other compensatory measures to…
View details →DOI: 10.1096/fasebj.27.1_supplement.1153.5 Negative / Null Result Report
Rosario Milelli · 2026 · Journal of Artificial Intelligence, Virtual Reality, and Human-Centered Computing
ChatGPT, developed by OpenAI, has become a central tool in my professional workflow, supporting scholarly research, editorial writing, and creative projects. Drawing on extensive practical use, this perspective highlights both its…
View details →DOI: 10.66311/3069-2318.02.01.02 Negative / Null Result Report
Mohd Faris Dziauddin · 2023 · PLANNING MALAYSIA
It is generally believed that public transport investment such as urban rail transit systems can improve accessibility, particularly in larger and denser metropolitan areas. The improved accessibility provided by urban rail transit systems…
View details →DOI: 10.21837/pm.v21i25.1243 Negative / Null Result Report
Larry Chen, Emily Berzolla, Griffith Gosnell et al. · 2025 · Journal of Hip Preservation Surgery
Abstract Background While hip arthroscopy (HA) has improved outcomes in femoroacetabular impingement syndrome (FAIS), advanced age has been considered a negative predictor of outcomes. The purpose of this study was to evaluate long-term…
View details →DOI: 10.1093/jhps/hnaf069.053 Negative / Null Result ReportOpen accessComputer Science
Amy Zhang, Shagun Sodhani, Khimya Khetarpal et al. · 2020 · arXiv
Many control tasks exhibit similar dynamics that can be modeled as having common latent structure. Hidden-Parameter Markov Decision Processes (HiP-MDPs) explicitly model this structure to improve sample efficiency in multi-task settings. However, this setting makes strong assumptions on the observability of the state that limit its application in real-world scenarios with rich observation spaces. In this work, we leverage ideas of common structure from the HiP-MDP setting, and extend it to enable robust state abstractions inspired by Block MDPs. We derive instantiations of this new framework f
Negative / Null Result ReportOpen accessComputer Science
Adam Karczmarz · 2021 · arXiv
We consider the directed minimum weight cycle problem in the fully dynamic setting. To the best of our knowledge, so far no fully dynamic algorithms have been designed specifically for the minimum weight cycle problem in general digraphs. One can achieve $\tilde{O}(n^2)$ amortized update time by simply invoking the fully dynamic APSP algorithm of Demetrescu and Italiano [J. ACM'04]. This bound, however, yields no improvement over the trivial recompute-from-scratch algorithm for sparse graphs. Our first contribution is a very simple deterministic $(1+ε)$-approximate algorithm supporting vertex
Negative / Null Result ReportOpen accessComputer Science
Raghav Gupta, Akanksha Jain, Abraham Gonzalez et al. · 2026 · arXiv
Agile hardware design flows are a critically needed force multiplier to meet the exploding demand for compute. Recently, agentic generative AI systems have demonstrated significant advances in algorithm design, improving code efficiency, and enabling discovery across scientific domains. Bridging these worlds, we present ArchAgent, an automated computer architecture discovery system built on AlphaEvolve. We show ArchAgent's ability to automatically design/implement state-of-the-art (SoTA) cache replacement policies (architecting new mechanisms/logic, not only changing parameters), broadly withi
Negative / Null Result ReportOpen accessComputer Science
Esther Ezra, Micha Sharir · 2021 · arXiv
We consider several problems that involve lines in three dimensions, and present improved algorithms for solving them. The problems include (i) ray shooting amid triangles in $R^3$, (ii) reporting intersections between query lines (segments, or rays) and input triangles, as well as approximately counting the number of such intersections, (iii) computing the intersection of two nonconvex polyhedra, (iv) detecting, counting, or reporting intersections in a set of lines in $R^3$, and (v) output-sensitive construction of an arrangement of triangles in three dimensions. Our approach is based on the
Negative / Null Result ReportOpen accessPhysics
Tim Gould · 2012 · arXiv
The "ACFD-RPA" correlation energy functional has been widely applied to a variety of systems to successfully predict energy differences, and less successfully predict absolute correlation energies. Here we present a parameter-free exchange-correlation kernel that systematically improves absolute correlation energies, while maintaining most of the good numerical properties that make the ACFD-RPA numerically tractable. The "RXH" kernel is constructed to approximate the true exchange kernel via a carefully weighted, easily computable radial averaging. Correlation energy errors of atoms with two t
Negative / Null Result ReportOpen accessPhysics
Ulrich H. E. Hansmann · 1997 · arXiv
We discuss the use of Tsallis generalized mechanics in simulated annealing algorithms. For a small peptide it is shown that older implementations are not more effective than regular simulated annealing in finding ground state configurations. We propose a new implementation which leads to an improvement over regular simulated annealing.
Negative / Null Result ReportOpen accessComputer Science
Donny Cheung, Dmitri Maslov, Jimson Mathew et al. · 2007 · arXiv
We consider a quantum polynomial-time algorithm which solves the discrete logarithm problem for points on elliptic curves over $GF(2^m)$. We improve over earlier algorithms by constructing an efficient circuit for multiplying elements of binary finite fields and by representing elliptic curve points using a technique based on projective coordinates. The depth of our proposed implementation, executable in the Linear Nearest Neighbor (LNN) architecture, is $O(m^2)$, which is an improvement over the previous bound of $O(m^3)$ derived assuming no architectural restrictions.
Negative / Null Result ReportOpen accessPhysics
Surachate Limkumnerd · 2026 · arXiv
Fluctuation relations imply the second-law inequality $\langleΣ_T\rangle\ge0$, but path extrema can also constrain how large the mean entropy production can be. For steady-state processes with entropy-production martingale $M_t=e^{-Σ_t}$, we show that knowing only the positive running maximum of $Σ_t$ gives no improvement over the trivial endpoint bound: rare negative entropy-production excursions can still carry the exponential weight required by the fluctuation relation. Using the running extrema $L_T=\inf M_t$ and $H_T=\sup M_t$, we derive a path-extrema upper envelope $\mathcal{U}_{\rm ext
Negative / Null Result ReportOpen accessComputer Science
Zohar Feldman, Carmel Domshlak · 2013 · arXiv
Popular Monte-Carlo tree search (MCTS) algorithms for online planning, such as epsilon-greedy tree search and UCT, aim at rapidly identifying a reasonably good action, but provide rather poor worst-case guarantees on performance improvement over time. In contrast, a recently introduced MCTS algorithm BRUE guarantees exponential-rate improvement over time, yet it is not geared towards identifying reasonably good choices right at the go. We take a stand on the individual strengths of these two classes of algorithms, and show how they can be effectively connected. We then rationalize a principle
Negative / Null Result ReportOpen accessComputer Science
Ravi Shankar Mishra, Kartik Mehta, Nikhil Rasiwasia · 2021 · arXiv
In this paper, we present SANTA, a scalable framework to automatically normalize E-commerce attribute values (e.g. "Win 10 Pro") to a fixed set of pre-defined canonical values (e.g. "Windows 10"). Earlier works on attribute normalization focused on fuzzy string matching (also referred as syntactic matching in this paper). In this work, we first perform an extensive study of nine syntactic matching algorithms and establish that 'cosine' similarity leads to best results, showing 2.7% improvement over commonly used Jaccard index. Next, we argue that string similarity alone is not sufficient for a
Negative / Null Result ReportOpen accessComputer Science
Max Hopkins, Daniel Kane, Shachar Lovett et al. · 2021 · arXiv
The explosive growth of easily-accessible unlabeled data has lead to growing interest in active learning, a paradigm in which data-hungry learning algorithms adaptively select informative examples in order to lower prohibitively expensive labeling costs. Unfortunately, in standard worst-case models of learning, the active setting often provides no improvement over non-adaptive algorithms. To combat this, a series of recent works have considered a model in which the learner may ask enriched queries beyond labels. While such models have seen success in drastically lowering label costs, they tend
Negative / Null Result ReportOpen accessComputer Science
Victor Lagerkvist, Johanna Groven, Leif Eriksson · 2026 · arXiv
The region connection calculus ($RCC$) and Allen's interval algebra ($IA$) are two well-known NP-hard spatial-temporal qualitative reasoning problems. They are solvable in $2^{O(n \log n)}$ time, where $n$ is the number of variables, and $IA$ is additionally known to be solvable in $o(n)^n$ time. However, no improvement over exhaustive search is known for $RCC$, and if they are also solvable in single exponential time $2^{O(n)}$ is unknown. We investigate multiple avenues towards reaching such bounds. First, we show that branching is insufficient since there are too many non-redundant constrai
Negative / Null Result ReportOpen accessMathematics
Shibdas Roy, Ian R. Petersen, Elanor H. Huntington · 2015 · arXiv
We study a coherent-classical estimation scheme for a class of linear quantum systems, where the estimator is a mixed quantum-classical system that may or may not involve coherent feedback. We show that when the quantum plant or the quantum part of the estimator (coherent controller) is an annihilation operator only system, coherent-classical estimation without coherent feedback can provide no improvement over purely-classical estimation. Otherwise, coherent-classical estimation without feedback can be better than classical-only estimation for certain homodyne detector angles, although the for
Negative / Null Result ReportOpen accessPhysics
Md Nahid Haque Shazon, Piyush Kumar, Luqiao Liu et al. · 2025 · arXiv
This paper presents physical modeling and benchmarking for two-terminal spin-orbit torque magnetic random-access memory (2T-SOT-MRAM). The results indicate that the common SOT materials that provide only in-plane torque can provide little to no improvement over spin-transfer-torque (STT) MRAM in terms of write energy. However, emerging SOT materials that provide out-of-plane torques with efficiencies as small as 0.1 can result in significant improvements in the write energy for such 2-terminal devices, especially when the magnet lateral dimensions are scaled down to 30 or 20 nm. Additionally,
Negative / Null Result ReportOpen accessComputer Science
Elad Hazan, Tomer Koren, Kfir Y. Levy · 2014 · arXiv
The logistic loss function is often advocated in machine learning and statistics as a smooth and strictly convex surrogate for the 0-1 loss. In this paper we investigate the question of whether these smoothness and convexity properties make the logistic loss preferable to other widely considered options such as the hinge loss. We show that in contrast to known asymptotic bounds, as long as the number of prediction/optimization iterations is sub exponential, the logistic loss provides no improvement over a generic non-smooth loss function such as the hinge loss. In particular we show that the c
Negative / Null Result ReportOpen accessComputer Science
Shibdas Roy, Ian R. Petersen, Elanor H. Huntington · 2014 · arXiv
We consider a coherent-classical estimation scheme for a class of linear quantum systems. It comprises an estimator that is a mixed quantum-classical system without involving coherent feedback. The estimator yields a classical estimate of a variable for the quantum plant. We demonstrate that for a passive plant that can be characterized by annihilation operators only, such coherent-classical estimation provides no improvement over purely-classical estimation. An example is also given which shows that if the plant is not assumed to be an annihilation operator only quantum system, it is possible
