Tootfinder

The hidden subgroup problem for infinite groups
Greg Kuperberg (UC Davis)
https://arxiv.org/abs/2507.18499 https://arxiv.org/pdf/2507.18499

The hidden subgroup problem for infinite groups
Following the example of Shor's algorithm for period-finding in the integers, we explore the hidden subgroup problem (HSP) for discrete infinite groups. On the hardness side, we show that HSP is NP-hard for the additive group of rational numbers, and for normal subgroups of non-abelian free groups. We also indirectly reduce a version of the short vector problem to HSP in $\mathbb{Z}^k$ with pseudo-polynomial query cost. On the algorithm side, we generalize the Shor-Kitaev algorithm for HSP in $…

A Robust Method for Pitch Tracking in the Frequency Following Response using Harmonic Amplitude Summation Filterbank
Sajad Sadeghkhani, Maryam Karimi Boroujeni, Hilmi R. Dajani, Saeid R. Seydnejad, Christian Gigu\`ere
https://arxiv.org/abs/2506.19253

A Robust Method for Pitch Tracking in the Frequency Following Response using Harmonic Amplitude Summation Filterbank
The Frequency Following Response (FFR) reflects the brain's neural encoding of auditory stimuli including speech. Because the fundamental frequency (F0), a physical correlate of pitch, is one of the essential features of speech, there has been particular interest in characterizing the FFR at F0, especially when F0 varies over time. The standard method for extracting F0 in FFRs has been the Autocorrelation Function (ACF). This paper investigates harmonic-structure-based F0 estimation algorithms,…

Algorithmic Collusion is Algorithm Orchestration
Cesare Carissimo, Fryderyk Falniowski, Siavash Rahimi, Heinrich Nax
https://arxiv.org/abs/2508.14766 https://

Algorithmic Collusion is Algorithm Orchestration
This paper proposes a fresh `meta-game' perspective on the problem of algorithmic collusion in pricing games a la Bertrand. Economists have interpreted the fact that algorithms can learn to price collusively as tacit collusion. We argue instead that the co-parametrization of algorithms -- that we show is necessary to obtain algorithmic collusion -- requires algorithm designer(s) to engage in explicit collusion by algorithm orchestration. To highlight this, we model a meta-game of algorithm para…

Exploring the Potential of LLMs for Serendipity Evaluation in Recommender Systems
Li Kang, Yuhan Zhao, Li Chen
https://arxiv.org/abs/2507.17290 https://arx…

Exploring the Potential of LLMs for Serendipity Evaluation in Recommender Systems
Serendipity plays a pivotal role in enhancing user satisfaction within recommender systems, yet its evaluation poses significant challenges due to its inherently subjective nature and conceptual ambiguity. Current algorithmic approaches predominantly rely on proxy metrics for indirect assessment, often failing to align with real user perceptions, thus creating a gap. With large language models (LLMs) increasingly revolutionizing evaluation methodologies across various human annotation tasks, we…

Scalable Bayesian inference on high-dimensional multivariate linear regression
Xuan Cao, Kyoungjae Lee
https://arxiv.org/abs/2508.16446 https://arxiv.org/p…

Scalable Bayesian inference on high-dimensional multivariate linear regression
We consider jointly estimating the coefficient matrix and the error precision matrix in high-dimensional multivariate linear regression models. Bayesian methods in this context often face computational challenges, leading to previous approaches that either utilize a generalized likelihood without ensuring the positive definiteness of the precision matrix or rely on maximization algorithms targeting only the posterior mode, thus failing to address uncertainty. In this work, we propose two Bayesi…

Who Leads in the Shadows? ERGM and Centrality Analysis of Congressional Democrats on Bluesky
Gordon Hew, Ian McCulloh
https://arxiv.org/abs/2507.16858 https://

Who Leads in the Shadows? ERGM and Centrality Analysis of Congressional Democrats on Bluesky
Following the 2024 U.S. presidential election, Democratic lawmakers and their supporters increasingly migrated from mainstream social media plat-forms like X (formerly Twitter) to decentralized alternatives such as Bluesky. This study investigates how Congressional Democrats use Bluesky to form networks of influence and disseminate political messaging in a platform environment that lacks algorithmic amplification. We employ a mixed-methods approach that combines social network analysis, expo-ne…

#Wordle 1,465 4/6*
⬜⬜⬜⬜⬜ <1% of 209,973 (754)
⬜🟨🟨⬜⬜ 1% of 157 (27)
⬜🟨⬜🟩🟨 0 of 1 (1)
🟩🟩🟩🟩🟩
WordleBot
Skill 84/99
Luck 50/99
It's interesting, the paths that lead you to the solution. Except for the bot, following an algorithm and knowing all the possible words as it goes, even those picking the same starting word follow different paths to the answer. I suspect I'd follow a different path next week from what I did today even if I used the same starting word.

Why use hyperlinking if you can create videos recording screens recording screens, just to be able to document other people documenting your own work. The modern internet is just sooo amazing!
#Actiniaria #GenerativeArt

Data Compression with Relative Entropy Coding
Gergely Flamich
https://arxiv.org/abs/2506.16309 https://arxiv.org/pdf/2506.16309

Data Compression with Relative Entropy Coding
Over the last few years, machine learning unlocked previously infeasible features for compression, such as providing guarantees for users' privacy or tailoring compression to specific data statistics (e.g., satellite images or audio recordings of animals) or users' audiovisual perception. This, in turn, has led to an explosion of theoretical investigations and insights that aim to develop new fundamental theories, methods and algorithms better suited for machine learning-based compressors. In…

Evaluation of Modular Polynomials from Supersingular Elliptic Curves
Maria Corte-Real Santos, Jonathan Komada Eriksen, Antonin Leroux, Michael Meyer, Lorenz Panny
https://arxiv.org/abs/2506.15429

Evaluation of Modular Polynomials from Supersingular Elliptic Curves
We present several new algorithms to evaluate modular polynomials of level $\ell$ modulo a prime $p$ on an input $j$. More precisely, we introduce two new generic algorithms, sharing the following similarities: they are based on a CRT approach; they make use of supersingular curves and the Deuring correspondence; and, their memory requirements are optimal. The first algorithm combines the ideas behind a hybrid algorithm of Sutherland in 2013 with a recent algorithm to compute modular polyno…