Tootfinder

CLF-RL: Control Lyapunov Function Guided Reinforcement Learning
Kejun Li, Zachary Olkin, Yisong Yue, Aaron D. Ames
https://arxiv.org/abs/2508.09354 https://

CLF-RL: Control Lyapunov Function Guided Reinforcement Learning
Reinforcement learning (RL) has shown promise in generating robust locomotion policies for bipedal robots, but often suffers from tedious reward design and sensitivity to poorly shaped objectives. In this work, we propose a structured reward shaping framework that leverages model-based trajectory generation and control Lyapunov functions (CLFs) to guide policy learning. We explore two model-based planners for generating reference trajectories: a reduced-order linear inverted pendulum (LIP) mode…

Me: "I'd like to know what resolution this video file is"
ffprobe:

ffprobe version 5.1.2-3ubuntu1 Copyright (c) 2007-2022 the FFmpeg developers
  built with gcc 12 (Ubuntu 12.2.0-14ubuntu2)
  configuration: --prefix=/usr --extra-version=3ubuntu1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libglslang --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librist --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libsvtav1 --ena

Lyapunov Exponents, Phase Transitions, and Chaos Bound of ModMax AdS Black Holes
Gorima Bezboruah, Mozib Bin Awal, Prabwal Phukon
https://arxiv.org/abs/2508.07832 https://

Lyapunov Exponents, Phase Transitions, and Chaos Bound of ModMax AdS Black Holes
We study the thermodynamic phase transition of ModMax anti-de Sitter (AdS) black holes using Lyapunov exponents of massless and massive particles in unstable circular orbits. Our results demonstrate that the thermal profile of the Lyapunov exponent serves as an efficient probe of the black hole's phase structure. We calculate the discontinuity in the Lyapunov exponent across the transition and show that it acts as an order parameter, exhibiting a critical exponent $δ=1/2$ in the vicinity of th…

A Review On Safe Reinforcement Learning Using Lyapunov and Barrier Functions
Dhruv S. Kushwaha, Zoleikha A. Biron
https://arxiv.org/abs/2508.09128 https://…

A Review On Safe Reinforcement Learning Using Lyapunov and Barrier Functions
Reinforcement learning (RL) has proven to be particularly effective in solving complex decision-making problems for a wide range of applications. From a control theory perspective, RL can be considered as an adaptive optimal control scheme. Lyapunov and barrier functions are the most commonly used certificates to guarantee system stability for a proposed/derived controller and constraint satisfaction guarantees, respectively, in control theoretic approaches. However, compared to theoretical gua…

Trapping, chaos and averaging in bubbling AdS spaces
David Berenstein, Mihailo \v{C}ubrovi\'c, Vladan Djuki\'c
https://arxiv.org/abs/2508.09669 https://

Trapping, chaos and averaging in bubbling AdS spaces
We discuss chaos and ensemble averaging in 1/2 BPS bubbling $AdS$ spaces of Lin, Lunin and Maldacena (LLM) by studying trapped and escaping null geodesics and estimating their decay rates. We find typical chaotic scattering behavior and confirm the Pesin relation between escape rates, Lyapunov exponents and Kolmogorov-Sinai entropy. On the other hand, for geodesics in coarse-grained (grayscale) LLM geometries (which exhibit a naked singularity) chaos is strongly suppressed, which is consistent …

Lapinpöllön pesintä keskeytti hakkuut Pohjois-Savossa, sitten rengastetut poikaset löytyivät puun juurelta tapettuina https://yle.fi/a/74-20171384?origin=rss/Mastodon
Yksityishenkilöt tarjoavat 1 000 euroa vihjeestä, joka johtaa lapinpöllön poikasten tappajan jäljille …

Lapinpöllön pesintä keskeytti hakkuut Pohjois-Savossa, sitten rengastetut poikaset löytyivät puun juurelta tapettuina
Metsähakkuut keskeytyivät, kun Pielaveden ja Kiuruveden rajamailta löytyi lapinpöllön pesä. Poikaset rengastettiin, mutta pian sen jälkeen ne löytyivät puun juurelta surmattuina.

The Fundamental Theorem of Dynamical Systems: all at once and all in the same place
Andrew D. Lewis
https://arxiv.org/abs/2508.10525 https://arxiv.org/pdf/…

The Fundamental Theorem of Dynamical Systems: all at once and all in the same place
The so-called Fundamental Theorem of Dynamical Systems -- which(1) relates attractors and repellers to the chain recurrent set and (2) gives the existence of a complete Lyapunov function -- can be seen as a means of separating out ``recurrent'' and ``transient'' dynamics. An overview of this theorem is given in its various guises, continuous-time/discrete-time and flows/semiflows. As part of this overview, a unified approach is developed for working simultaneously with both the continuous-time …

Lyapunov stability analysis of the chaotic flow past two square cylinders
Sidhartha Sahu, George Papadakis
https://arxiv.org/abs/2508.05892 https://arxiv.o…

Lyapunov stability analysis of the chaotic flow past two square cylinders
We investigate the stability of the flow past two side-by-side square cylinders (at Reynolds number 200 and gap ratio 1) using tools from dynamical systems theory. The flow is highly irregular due to the complex interaction between the flapping jet emanating from the gap and the vortices shed in the wake. We first perform Spectral Proper Orthogonal Decomposition (SPOD) to understand the flow characteristics. We then conduct Lyapunov stability analysis by linearizing the Navier-Stokes equations …

Study on deflection angle, shadow, quasinormal modes, and greybody factor of the black hole surrounded by quintessence in Rastall gravity
Susmita Sarkar, Nayan Sarkar, Tuhina Manna, Moumita Sarkar, Farook Rahaman
https://arxiv.org/abs/2508.09221

Study on deflection angle, shadow, quasinormal modes, and greybody factor of the black hole surrounded by quintessence in Rastall gravity
The present study focuses on investigating the deflection angle in the weak-field approximation, shadow, quasinormal modes using Lyapunov exponents, and lower bound of the greybody factor for a charged black hole surrounded by a quintessence field in Rastall gravity. The weak deflection angles are calculated using the Gauss-Bonnet method. They decrease with increasing impact parameter b and charge Q, but gradually increase with increasing black hole mass m. Notably, the presence of a surroundin…

Some remarks on stochastic converse Lyapunov theorems
Pavel Osinenko, Grigory Yaremenko
https://arxiv.org/abs/2506.06053 https://arxi…

Some remarks on stochastic converse Lyapunov theorems
In this brief note, we investigate some constructions of Lyapunov functions for stochastic discrete-time stabilizable dynamical systems, in other words, controlled Markov chains. The main question here is whether a Lyapunov function in some statistical sense exists if the respective controlled Markov chain admits a stabilizing policy. We demonstrate some constructions extending on the classical results for deterministic systems. Some limitations of the constructed Lyapunov functions for stabili…