Tootfinder

"It is fair to say that Microsoft spent at least the first five years of its history in relative obscurity. The first appearance of the name “Microsoft” on the pages of Byte was a short mention of their BASIC interpreter in an advertising on page 47 of the May 1977 issue. In contrast, page 34 of the same issue included an article about the Apple II by Steve Wozniak. The Woz and Gary Kildall were the biggest stars of the microcomputer industry at the end of the 1970s."
https://deprogrammaticaipsum.com/where-does-microsoft-want-to-go-today/

Skype Is Officially Shutting Down for Good https://www.howtogeek.com/skype-shut-down-may-5-2025/
I wasn't a fan or anything, but like for many others, it was my first video conferencing app and I can't help but feel a certain sense of melancholy.

Confirmed: the May average of atmospheric CO2 at Mauna Loa was 430.5 ppm, first time above 430 ppm in 15 million years, and a big jump from a year ago, again: 3.6 ppm!
Overall, we're still speeding in the wrong direction.

Trade Pitch Has Raiders $25 Million Defender Reunite With Dave Ziegler https://heavy.com/sports/nfl/las-vegas-raiders/tyree-wilson-titans-trade-rumors/?adt_ei=[email]

The rate of descent did not slow as much as expected,
and the spacecraft probably made a hard landing.
The laser instrument that measured how high Resilience was above the surface was slow in making its measurements,
which may have contributed to the problem.
“At this point, we do not know clearly about the cause,”
Takeshi Hakamada, the chief executive of Ispace, said in translated remarks.
The loss of the second mission could lead NASA to rethink its pla…

Ispace of Japan’s Moon Lander Resilience Has Crashed
The loss of the Resilience spacecraft by Ispace repeated a crash into the moon in 2023 of the company’s first robotic lunar landing mission.

Q&A with Mary Meeker on publishing her first Trends report since 2019, its focus on the AI revolution, why OpenAI may have an insurmountable lead, and more (Dan Primack/Axios)
https://www.axios.com/2025/05/30/mary-meeker-trends-report-openai

Q&A with Mary Meeker on the AI revolution
The famed internet analyst turned VC just published her first Trends report since 2019.

First Canada Goose babies and the Baltimore Orioles are chattering up a storm. Must be early May in south-central Ontario.
#canada #birds

This https://arxiv.org/abs/2505.22984 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csLG_…

A Computational Approach to Improving Fairness in K-means Clustering
The popular K-means clustering algorithm potentially suffers from a major weakness for further analysis or interpretation. Some cluster may have disproportionately more (or fewer) points from one of the subpopulations in terms of some sensitive variable, e.g., gender or race. Such a fairness issue may cause bias and unexpected social consequences. This work attempts to improve the fairness of K-means clustering with a two-stage optimization formulation--clustering first and then adjust cluster …

This https://arxiv.org/abs/2504.08472 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csIT_…

Simultaneous Rational Number Codes: Decoding Beyond Half the Minimum Distance with Multiplicities and Bad Primes
In this paper, we extend the work of (Abbondati et al., 2024) on decoding simultaneous rational number codes by addressing two important scenarios: multiplicities and the presence of bad primes (divisors of denominators). First, we generalize previous results to multiplicity rational codes by considering modular reductions with respect to prime power moduli. Then, using hybrid analysis techniques, we extend our approach to vectors of fractions that may present bad primes. Our contributions incl…

Cowboys new backup QB outranks 10 drafted higher, including 2 first-round picks https://cowboyswire.usatoday.com/story/sports/nfl/cowboys/2025/06/04/cowboys-milton-backup-qb-rankings-2025/84029638007/

UniSite: The First Cross-Structure Dataset and Learning Framework for End-to-End Ligand Binding Site Detection
Jigang Fan, Quanlin Wu, Shengjie Luo, Liwei Wang
https://arxiv.org/abs/2506.03237

UniSite: The First Cross-Structure Dataset and Learning Framework for End-to-End Ligand Binding Site Detection
The detection of ligand binding sites for proteins is a fundamental step in Structure-Based Drug Design. Despite notable advances in recent years, existing methods, datasets, and evaluation metrics are confronted with several key challenges: (1) current datasets and methods are centered on individual protein-ligand complexes and neglect that diverse binding sites may exist across multiple complexes of the same protein, introducing significant statistical bias; (2) ligand binding site detection …

Global Kinetic Simulations of Monster Shocks and Their Emission
Dominic Bernardi, Yajie Yuan, Alexander Y. Chen
https://arxiv.org/abs/2506.04175 https://…

Global Kinetic Simulations of Monster Shocks and Their Emission
Fast magnetosonic waves are one of the two low-frequency plasma modes that can exist in a neutron star magnetosphere. It was recently realized that these waves may become nonlinear within the magnetosphere and steepen into some of the strongest shocks in the universe. These shocks, when in the appropriate parameter regime, may emit GHz radiation in the form of precursor waves. We present the first global Particle-in-Cell simulations of the nonlinear steepening of fast magnetosonic waves in a di…

Happy First Of May!
#may #firstOfMay

from my link log —
10 years of stable Rust: an infrastructure story.
https://rustfoundation.org/media/10-years-of-stable-rust-an-infrastructure-story/
saved 2025-05-15

10 Years of Stable Rust: An Infrastructure Story - The Rust Foundation
A note from the Rust Foundation: Today, May 15, 2025, marks 10 years since the first stable release of Rust. To commemorate this milestone, we are excited to share the following guest blog contributed by Graydon Hoare, initial author of the Rust programming language.   Rust turns 10 today, or at…

Why Lamar Jackson could get $70 million per year, plus ranking 12 teams who could win their first Super Bowl

https://www.cbssports.com/nfl/news…

“TNC is where it all comes to life.”

In this video message, our CEO Lise Fuhr shares excitement ahead of her very first TNC, and why this global gathering matters so much to our Research & Education community.

Watch her personal welcome message below, as we all get ready for next week’s #TNC25 in Brighton 🇬🇧

And if you’re not coming in person, don’t forget to g…

Vermont and Nebraska: Diverging Experiments in State Age-Appropriate Design Codes
https://fpf.org/blog/vermont-and-nebraska-diverging-experiments-in-state-age-appropriate-design-codes/
@…

Last morning in Qaanaaq, time to go home, but first a massive clean up is due! Lots of notes to write up, still some data to download, need to go and repair a cable too. May have time to update and round off the full #FieldDiary later.
But first a peaceful shot from last night, when the narwhals were in the bay again...

I'm getting a bit tired of government censorship of the Arts community
https://www.theguardian.com/australia-news/2025/may/21/state-library-of-queensland-karen-wyld-first-nations-writer-…

we thanked them for their service and said goodbye to these books

OLi3-decorated Irida-graphene for High-capacity Hydrogen Storage: A First-principles Study
Jose A. S. Laranjeira, Warda Elaggoune, Nicolas F. Martins, Xihao Chen, Julio R. Sambrano
https://arxiv.org/abs/2506.02375

OLi3-decorated Irida-graphene for High-capacity Hydrogen Storage: A First-principles Study
Efficient hydrogen storage in solid-state materials is essential for next-generation energy systems, yet achieving a high gravimetric capacity with optimal adsorption characteristics remains a critical challenge. Although Li-decorated irida-graphene (IG) has shown promising hydrogen storage potential, its capacity is limited to $\sim$ 7wt\%, which, despite exceeding the U.S. DOE target, remains inadequate for large-scale applications. Additionally, Li clustering over extended cycles may comprom…

if you want to read the new translation of Capital, it's 50% off until May 31st, which means there is only half as much socially-necessary labor time embodied in it
https://press.princeton.edu/books/hardcover/9780691190075/capital

Ugh, memes:
1) I’ve had that song stuck in my head all freaking WEEK. Every time I close my eyes, there’s *NSYNC
(which I spelled w*rong the first time)
2) I’m so glad the 4th of May was on a weekend this year.

Huntsman may need to be irradiated
Shunyi Lan, Xiangcun Meng
https://arxiv.org/abs/2506.00537 https://arxiv.org/pdf/2506.00537…

Huntsman may need to be irradiated
Millisecond pulsars are rapidly rotating neutron stars, and it is now widely accepted that their extremely short rotation periods result from the accretion of material from a companion star. Binary evolution theory predicts that millisecond pulsars can have various types of companion stars. However, in observations, binary pulsars with giant companions, referred to as ``huntsman pulsars'', are extremely rare. Following the initial discovery of the first huntsman pulsar, 1FGL J1417.7-4407, a sec…

A first view on the density of 5-planar graphs
Aaron B\"ungener, Jakob Franz, Michael Kaufmann, Maximilian Pfister
https://arxiv.org/abs/2505.24364 ht…

A first view on the density of 5-planar graphs
$k$-planar graphs are generalizations of planar graphs that can be drawn in the plane with at most $k > 0$ crossings per edge. One of the central research questions of $k$-planarity is the maximum edge density, i.e., the maximum number of edges a $k$-planar graph on $n$ vertices may have. While there are numerous results for the classes of general $k$-planar graphs for $k\leq 2$, there are only very few results for increasing $k=3$ or $4$ due to the complexity of the classes. We make a first st…

Stabilization of Linear Switched Systems with Long Input Delay via Average or Averaging Predictor Feedbacks
Andreas Katsanikakis, Nikolaos Bekiaris-Liberis
https://arxiv.org/abs/2506.03908

Stabilization of Linear Switched Systems with Long Input Delay via Average or Averaging Predictor Feedbacks
We develop delay-compensating feedback laws for linear switched systems with time-dependent switching. Because the future values of the switching signal, which are needed for constructing an exact predictor-feedback law, may be unavailable at current time, the key design challenge is how to construct a proper predictor state. We resolve this challenge constructing two alternative, average predictor-based feedback laws. The first is viewed as a predictor-feedback law for a particular average sys…

This https://arxiv.org/abs/2503.10182 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

$PSL_2$ tropicalization and lines on surfaces
The paper is based on a talk given by the first author at the Gökova Geometry \& Topology conference in May 2024. The subject is an interplay between the ideas of tropical geometry and two-by-two matrices with an intention to explore new types of geometries. More concretely, the article gives a preliminary account for a non-abelian version of phase tropicalization for subvarieties of $PSL_2.$

Alas, too late for members of the current United States mis-administration.
https://www.theguardian.com/society/2025/may/21/world-first-gonorrhoea-vaccine-rollout-england

This week I've learned that "per-connection randomized MAC" – while being great for privacy – can be an issue for login-based WiFi networks. First of all it requires you to login again every time you reconnect, but you may also get issues with let's say hotel WiFis that limit the number of devices on one account 😅
I think this is mostly an issue caused by the captive portal implementation.
CC @…

This https://arxiv.org/abs/2306.14853 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Near-Optimal Nonconvex-Strongly-Convex Bilevel Optimization with Fully First-Order Oracles
In this work, we consider bilevel optimization when the lower-level problem is strongly convex. Recent works show that with a Hessian-vector product (HVP) oracle, one can provably find an $ε$-stationary point within ${\mathcal{O}}(ε^{-2})$ oracle calls. However, the HVP oracle may be inaccessible or expensive in practice. Kwon et al. (ICML 2023) addressed this issue by proposing a first-order method that can achieve the same goal at a slower rate of $\tilde{\mathcal{O}}(ε^{-3})$. In this pap…

This first-rate student film is a must see for anyone using, or especially those planning, urban subway systems, and may even explain some #ttc oddities 😅 You know is a good action movie when the hero they call upon is a topologist!
Moebius (1996) #cinema
https://youtube.com/watch?v=SQrW0BLQtvA&si=x3wFV8jryg2gK5U-

Benford's Curse: Tracing Digit Bias to Numerical Hallucination in LLMs
Jiandong Shao, Yao Lu, Jianfei Yang
https://arxiv.org/abs/2506.01734 https://

Benford's Curse: Tracing Digit Bias to Numerical Hallucination in LLMs
Large Language Models (LLMs) exhibit impressive performance on complex reasoning tasks, yet they frequently fail on basic numerical problems, producing incorrect outputs. Inspired by Benford's Law -- a statistical pattern where lower digits occur more frequently as leading digits -- we hypothesize that the long-tailed digit distributions in web-collected corpora may be learned by LLMs during pretraining, leading to biased numerical generation. To investigate the hypothesis, we first examine whe…

This https://arxiv.org/abs/2002.10921 has been replaced.
link: https://scholar.google.com/scholar?q=a

A computer-friendly construction of the monster
Let $\mathbb{M}$ be the monster group which is the largest sporadic finite simple group, and has first been constructed in 1982 by Griess. In 1985, Conway has constructed a 196884-dimensional representation $ρ$ of $\mathbb{M}$ with matrix coefficients in $\mathbb{Z}[\frac{1}{2}]$. So these matrices may be reduced modulo any (not necessarily prime) odd number $p$, leading to representations of $\mathbb{M}$ in odd characteristic. The representation $ρ$ is based on representations of two maximal…

Paradromics implanted and removed its Connexus brain implant in a patient for ~10 minutes during epilepsy surgery on May 14, a first for the Neuralink rival (Emily Mullin/Wired)
https://www.wired.com/story/paradromics-neuralink-rival-tested-brain-impl…

A Neuralink Rival Just Tested a Brain Implant in a Person
Paradromics, a brain-computer-interface startup, inserted its brain implant in a person—briefly—in an early test of its technology.

This https://arxiv.org/abs/2411.18688 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csCR_…

Immune: Improving Safety Against Jailbreaks in Multi-modal LLMs via Inference-Time Alignment
With the widespread deployment of Multimodal Large Language Models (MLLMs) for visual-reasoning tasks, improving their safety has become crucial. Recent research indicates that despite training-time safety alignment, these models remain vulnerable to jailbreak attacks. In this work, we first highlight an important safety gap to describe that alignment achieved solely through safety training may be insufficient against jailbreak attacks. To address this vulnerability, we propose Immune, an infer…

NASA’s Goddard Institute for Space Studies (GISS)
has been a small-but-mighty source of world-changing scientific research for more than a half-century.
NASA scientists first moved into the building,
which another federal agency leases from GISS’s institutional partner, Columbia University, in 1966.
Last month, at the behest of the Trump administration,
NASA officials told GISS it had to move out before the end of May.
In response, more than 100 staffer…

NASA’s Goddard Institute for Space Studies Faces Eviction under Trump Plan
Since 1966 NASA’s Goddard Institute for Space Studies has been at the forefront of Earth and planetary science from its location in upper Manhattan. Now a Trump administration directive is ejecting its scientists to parts unknown

Ann Telnaes resigned from WaPo when this cartoon was rejected.
She wrote, “...My job is to hold powerful people and institutions accountable. For the first time, my editor prevented me from doing that critical job.”
Join us May 29th via Zoom for a conversation with her.
Sign up: tiny.cc/Telnaes

Microsoft finally ships controversial Windows 11 'Recall' feature after year-long delay — now rolling out to all Copilot PCs
https://www.windowscentral.com/software-apps/windows-11/windows-recall-general-availabilit…

Earlier this month, the Copyright Office issued the third part of its report on on AI: this one covering how generative AI may infringe on copyright and whether that's fair use (short answer: maybe, maybe not). I have a new article up summarizing the report.
https://www.…

Copyright Office's report discusses whether generative AI use is fair use
Earlier this month, the Copyright Office issued the third part of its report on AI. As with the first two parts, the Copyright Office discusses arguments from people who responded to its call for comments and then provides its analysis. The three main sections in this part focus on infringement, fair use, and licensing regimes. Here, I’m going to cover what the report says about the first two items: whether using copyrighted material in generative AI infringes on owners’ rights and whether…

Simulating High-Velocity Clouds in the Observational Plane: An Initial Study with the Smith Cloud
Lori E. Porter, Matthew Abruzzo, Greg L. Bryan, Mary Putman, Yong Zheng, Drummond Fielding
https://arxiv.org/abs/2506.00111

Simulating High-Velocity Clouds in the Observational Plane: An Initial Study with the Smith Cloud
High-velocity clouds (HVCs) may fuel future star formation in the Milky Way, but they must first survive their passage through the hot halo. While recent work has improved our understanding of the survival criterion for cloud-wind interactions, few observational comparisons exist that test this criterion. We therefore present an initial comparison of simulations with the Smith Cloud (SC; $d=$ 12.4 kpc, $l, b = 40^{\circ}, -13^{\circ}$) as mapped with the GALFA-HI survey. We use the Smith Cloud'…

Poiseuille flow of hyperbolic Ericksen-Leslie system in dimension two
Geng Chen, Tao Huang, Xiang Xu, Qingtian Zhang
https://arxiv.org/abs/2506.01223 https…

Poiseuille flow of hyperbolic Ericksen-Leslie system in dimension two
In this paper, we study the Poiseuille laminar flow in a tube for the full Ericksen-Leslie system. It is a parabolic-hyperbolic coupled system which may develop singularity in finite time. We will prove the global existence of energy weak solution, and the partial regularity of solution to system. We first construct global weak finite energy solutions by the Ginzburg- Landau approximation and the fixed-point arguments. Then we obtain the enhanced regularity of solution. Different from the solut…

Using the last of my free cinema tickets was tough... seeing The Accountant 2 tonight, I remember enjoying the first. But what then? May or may not actually attend, but booked a showing of The Amateur on Sunday night ending at 1am 😂 always wanted to do a late screening!

Good Morning #Canada
On May 27, 1957, at 6:00 a.m., the CHUM radio station (1050 AM) increased power from 1,000 watts to 2,500 watts and switched from a daytime station to 24 hours. At that same moment, radios all over Toronto started playing Elvis Presley singing “All Shook Up” as the "New CHUM" became Canada’s first Top 50 music format. The station launched hundreds of careers and introduced new music to young and old alike.
#CanadaIsAwesome #MusicHistory
https://chumtribute.com/chumtribute-history.html

Deaf President Now! review – passion and energy in stirring record of student protest;
Documentary follows the 1988 anti-audism revolt in the US after the world’s first deaf university appointed a hearing person to head it
https://www.theguardian.com/film/2025/…

🚨 Lansing: My favorite social event of the year is back this Saturday, May 31st!
Bike and Seek is a location-based scavenger hunt. First person or team to solve every clue scattered across the City of Lansing's bike infrastructure and get to the finish line wins. Register online!
https://bikeandseek.org

Are Mamba-based Audio Foundation Models the Best Fit for Non-Verbal Emotion Recognition?
Mohd Mujtaba Akhtar, Orchid Chetia Phukan, Girish, Swarup Ranjan Behera, Ananda Chandra Nayak, Sanjib Kumar Nayak, Arun Balaji Buduru, Rajesh Sharma
https://arxiv.org/abs/2506.02258

Are Mamba-based Audio Foundation Models the Best Fit for Non-Verbal Emotion Recognition?
In this work, we focus on non-verbal vocal sounds emotion recognition (NVER). We investigate mamba-based audio foundation models (MAFMs) for the first time for NVER and hypothesize that MAFMs will outperform attention-based audio foundation models (AAFMs) for NVER by leveraging its state-space modeling to capture intrinsic emotional structures more effectively. Unlike AAFMs, which may amplify irrelevant patterns due to their attention mechanisms, MAFMs will extract more stable and context-aware…

This https://arxiv.org/abs/2312.16863 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Existence and spectrality of infinite convolutions generated by infinitely many admissible pairs
In this paper, we study the spectrality of infinite convolutions generated by infinitely many admissible pairs which may not be compactly supported, where the spectrality means the corresponding square integrable function space admits a family of exponential functions as an orthonormal basis. First, we prove that the infinite convolution exists and is a spectral measure if the sequence of admissible pairs satisfies the remainder bounded condition, and it has a subsequence consisting of genera…

On different platforms, I see at least one post per day of someone willing to switch to #Linux. While seeing our community growing is nice, my first reaction is always: why didn't you take 3 seconds to read the post just before yours?
I may just become too old and grumpy but, generally speaking, I don't understand people who immediatly ask a question that has been answered thous…

This https://arxiv.org/abs/2409.02236 has been replaced.
initial toot: https://mastoxiv.page/@a…

Umklapp-driven first-order transition into a charge-density wave phase
Using phenomenological Landau free energy, we systematically analyze influence of so-called umklapp contributions on the phase diagram of a solid hosting a commensurate charge-density wave phase. The umklapp terms may change the transition into the ordered state from continuous (second-order) to discontinuous (first-order). Additional elements, such as critical and tricritical points, emerge on the phase diagram under suitable conditions. The proposed mechanism is generalized for the case of ne…

This https://arxiv.org/abs/2505.14686 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

HDO ice detected toward an isolated low-mass protostar with JWST
Water is detected in environments representing every stage of star and solar system formation, but its chemical evolution throughout these stages remains poorly constrained. Deuterium ratios offer a means of probing chemical links between water in different cosmic regions because of their sensitivity to physicochemical conditions. Here, we present the first detection of the 4.1 $μ$m HDO ice feature with JWST toward a low-mass protostar, L1527 IRS, which may eventually grow to a sun-like mass. …

Bochner-type theorems for distributional category
Ekansh Jauhari, John Oprea
https://arxiv.org/abs/2505.21763 https://arxiv.org/pdf/2…

Bochner-type theorems for distributional category
We show that in the presence of a geometric condition such as non-negative Ricci curvature, the distributional category of a manifold may be used to bound invariants, such as the first Betti number and macroscopic dimension, from above. Moreover, à la Bochner, when the bound is an equality, special constraints are imposed on the manifold. We show that the distributional category of a space also bounds the rank of the Gottlieb group, with equality imposing constraints on the fundamental group. …

DOGE's push from tape archives to cloud-based "permanent modern digital records" (not a thing) opens the door to increased software obsolescence, hacking, and climate impact. Greater transparency? Maybe—or these wannabe nerds just plan to surveil and monetize govt data

#TuneTuesday (May 20)
Until “Multo” (Ghost), the #PPop band #CupOfJoe hadn’t really entered into my music radar. But after I first heard this synth-pop tune—and I’ve been hearing it a lot lately on the radi…

Earlier this month, the Copyright Office issued the third part of its report on on AI: this one covering how generative AI may infringe on copyright and whether that's fair use (short answer: maybe, maybe not). I have a new article up summarizing the report.
https://www.…

Copyright Office's report discusses whether generative AI use is fair use
Earlier this month, the Copyright Office issued the third part of its report on AI. As with the first two parts, the Copyright Office discusses arguments from people who responded to its call for comments and then provides its analysis. The three main sections in this part focus on infringement, fair use, and licensing regimes. Here, I’m going to cover what the report says about the first two items: whether using copyrighted material in generative AI infringes on owners’ rights and whether…

Observation of pseudogap in Cr_{1-x}Y_xN magnetic alloy and its impact on the Seebeck coefficient by ab-initio calculations
Luis Felipe Leon-Pinzon, Elisabeth Restrepo-Parra, Andres Manuel Garay-Tapia
https://arxiv.org/abs/2506.00687

Observation of pseudogap in Cr_{1-x}Y_xN magnetic alloy and its impact on the Seebeck coefficient by ab-initio calculations
Thermoelectric materials require high electronic conductivity and low thermal conductivity. CrN has been shown to have low phononic thermal conductivity, making it a potential candidate for thermoelectric applications. In addition, similarities have been observed between YN and ScN suggesting that the CrYN alloy may have interesting thermoelectric properties. As CrYN has not been studied in detail at the level of thermoelectric properties, the first study on CrYN alloy of Seebeck coefficient an…

How bad are the cuts to NASA? And is this the first hint of Planet 9? | Night Sky News May 2025
Some projects already built and scheduled for launch might end up in storage https://www.youtube.com/watch?v=si6paqM2_ug

This is the first time it ever happened. Just browsing around GitHub I exceeded a "secondary rate limit".

Reappraising the Elatina series: Solar dynamo clocking and inference of orbital periods
F. Stefani, T. Weier, G. M. Horstmann, G. Mamatsashvili
https://arxiv.org/abs/2506.02628

Reappraising the Elatina series: Solar dynamo clocking and inference of orbital periods
We reconsider the 680 million year old Elatina series of sedimentary laminae from South Australia that show a remarkably stable periodicity with a main period of around 12 years, which is close to the Schwabe cycle, and a second period of 314 years that has been coined Elatina cycle. By analyzing the residuals of the series' minima from a linear trend, and deriving Dicke's ratio, we first show that the series exhibits a high degree of phase stability, except one single break point which may ind…

Learning to Charge More: A Theoretical Study of Collusion by Q-Learning Agents
Cristian Chica, Yinglong Guo, Gilad Lerman
https://arxiv.org/abs/2505.22909 …

Learning to Charge More: A Theoretical Study of Collusion by Q-Learning Agents
There is growing experimental evidence that $Q$-learning agents may learn to charge supracompetitive prices. We provide the first theoretical explanation for this behavior in infinite repeated games. Firms update their pricing policies based solely on observed profits, without computing equilibrium strategies. We show that when the game admits both a one-stage Nash equilibrium price and a collusive-enabling price, and when the $Q$-function satisfies certain inequalities at the end of experiment…

Voltage Control of the Boost Converter: PI vs. Nonlinear Passivity-based Control
Leyan Fang, Romeo Ortega, Robert Gri\~n\'o
https://arxiv.org/abs/2505.23112

Voltage Control of the Boost Converter: PI vs. Nonlinear Passivity-based Control
We carry-out a detailed analysis of direct voltage control of a Boost converter feeding a simple resistive load. First, we prove that using a classical PI control to stabilize a desired equilibrium leads to a very complicated dynamic behavior consisting of two equilibrium points, one of them always unstable for all PI gains and circuit parameter values. Interestingly, the second equilibrium point may be rendered stable -- but for all tuning gains leading to an extremely large value of the circu…

Resonant Island Trapping in a Fourth-Generation Synchrotron Light Source
E. C. Cort\'es Garc\'ia, N. Carmignani, F. Ewald, S. A. Antipov, K. Scheidt, S. White, I. V. Agapov
https://arxiv.org/abs/2505.12469

Resonant Island Trapping in a Fourth-Generation Synchrotron Light Source
We report the first direct observation of nonlinear resonance island trapping in a fourth-generation light source with working points far from the excited resonance and examine the nonlinear dynamics and properties of the trapped beam. The discovered dynamics of island trapping may help understand bunch purity and halo formation issues, create additional experimental capabilities for photon science applications, and present means of nonlinear characterization of the machine optics.