Tootfinder

Idea: statically typed language (or Python type checker?) Where types aren't declared, but can only be assigned by providing tests/examples that use that type. Examples could provide explicit type info where necessary, but code could not.
If it's not documented with an example, it's not safe to use with those types.

Quantum Graph Theory by Example
Gian Luca Spitzer, Ion Nechita
https://arxiv.org/abs/2603.23651 https://arxiv.org/pdf/2603.23651 https://arxiv.org/html/2603.23651
arXiv:2603.23651v1 Announce Type: new
Abstract: Quantum graphs have been introduced by Duan, Severini, and Winter to describe the zero-error behaviour of quantum channels. Since then, quantum graph theory has become a field of study in its own right. A substantial source of difficulty in working with quantum graphs compared to classical graphs stems from the fact that they are no longer discrete objects. This makes it generally difficult to construct insightful, non-trivial examples. We present a collection of non-trivial quantum graphs that can be thought of in discrete terms, and that can be expressed in the diagrammatic formalism introduced by Musto, Reutter, and Verdon. The examples arise as the quantum graphs acted on by increasingly smaller classical matrix groups, and are parametrised by triples of matrices $(A, B, C)$. The parametrisation reveals a clean decomposition of quantum graph structure into classical and genuinely quantum components: $A$ and $C$ are described by a classical weighted graph called the strange graph, while $B$ provides a purely quantum contribution with no classical analogue. Based on this model, we give exact formulas or establish bounds for quantum graph parameters, such as the number of connected components, the chromatic number, the independence number, and the clique number. Our results provide the first large, parametric families of quantum graphs for which standard graph parameters can be computed analytically.
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Since I fired up Chrome and enabled grid lanes to read Manuel’s post, I tried my 2019 reading order bookmarklet:
https://adrianroselli.com/2019/04/reading-order-bookmarklet.html
And it works!
You have to run it from the top of the page for the numbers t…

Hidden Higher-Order Vulnerabilities in Simplicial Complexes Revealed by Branch-Consistent Functional Robustness
Kaiming Luo
https://arxiv.org/abs/2603.24286 https://arxiv.org/pdf/2603.24286 https://arxiv.org/html/2603.24286
arXiv:2603.24286v1 Announce Type: new
Abstract: Robustness of higher-order networks is often quantified by the instantaneous smallest positive eigenvalue of the Hodge $1$-Laplacian under simplex deletion. We show that this observable is generically ill-defined: along a deletion trajectory, eigenvalue branches can switch, so the quantity being monitored may correspond to different nonharmonic modes at different steps. The primary issue is therefore definitional rather than algorithmic. We resolve it by fixing the first nonharmonic branch of the intact complex and following that same branch throughout the damage process, which defines a branch-consistent functional robustness. Triangle sensitivities then follow directly from first-order perturbation theory, making the resulting mode-sensitive deletion protocol a consequence of the observable itself rather than an independent heuristic. Across synthetic and empirical clique complexes, removing only a small fraction of triangles is sufficient to drive the tracked mode to collapse, while graph-level observables remain unchanged because the $1$-skeleton is exactly preserved. The same framework also reveals bridge-like localization of functionally critical simplices and provides a compact predictor of dynamical timescales.
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Enhanced left triangulated categories
Xiaofa Chen
https://arxiv.org/abs/2603.24300 https://arxiv.org/pdf/2603.24300 https://arxiv.org/html/2603.24300
arXiv:2603.24300v1 Announce Type: new
Abstract: In this short note, we study dg categories with homotopy kernels, whose homotopy categories are known to admit a natural left triangulated structure. Prototypical examples of such dg categories arise as dg quotients of exact dg categories. We demonstrate that the stablization of the homotopy category of such a dg category admits a canonical dg enhancement via its bounded derived dg category.
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Quantification of atmospheric carbon dioxide from the Geostationary Operational Environmental Satellite (GOES East)
Aaron Sonabend-W, Sean Campbell, John Platt, Christopher Van Arsdale, Anna M. Michalak
https://arxiv.org/abs/2605.23991 https://arxiv.org/pdf/2605.23991 https://arxiv.org/html/2605.23991
arXiv:2605.23991v1 Announce Type: new
Abstract: There is a growing urgency to track greenhouse gasses with the resolution, precision and accuracy needed to support independent verification of $CO_2$ fluxes at local to global scales. The current generation of space-based sensors, however, only provides sparse observations in space and time. This challenge has fueled interest in the potential use of data from existing missions originally developed for other applications for inferring global greenhouse gas variability. The Advanced Baseline Imager (ABI) onboard the Geostationary Operational Environmental Satellite (GOES-East), operational since 2017, provides full coverage of much of the western hemisphere at 10-minute intervals from geostationary orbit at 16 wavelengths at an approximately 2$km^2$ spatial resolution. Here, we leverage this high spatial coverage and temporal revisit to develop a single-pixel, physics-guided neural network to estimate dry-air column $CO_2$ mole fraction ($XCO_2$). The model employs a time series of GOES-East's 16 spectral bands, ECMWF ERA5 lower tropospheric meteorology, MODIS surface reflectance, solar and satellite viewing geometry, and day of year. Training used collocated GOES-East and OCO-2/OCO-3 observations. We also present case studies illustrating the use of the model to observe $XCO_2$ enhancements over urban areas and drawdown over agricultural regions. Overall, while the precision of GOES-East derived $XCO_2$ can never rival that of dedicated instruments, the unprecedented combination of contiguous geographic coverage, 10-minute temporal frequency, and multi-year record offers the potential to observe aspects of atmospheric $CO_2$ variability currently unseen from space.
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Nonlocal-coupling-based control of coherence resonance in an ensemble of non-excitable oscillators
Aleksey Ryabov, Vladimir V. Semenov
https://arxiv.org/abs/2603.24210 https://arxiv.org/pdf/2603.24210 https://arxiv.org/html/2603.24210
arXiv:2603.24210v1 Announce Type: new
Abstract: It is shown that nonlocal coupling provides for controlling the collective noise-induced dynamics of non-excitable oscillators in the regime of coherence resonance. This effect is demonstrated by means of numerical simulation on an example of coupled generalized Van der Pol oscillators near the saddle-node bifurcation of limit cycles. In particular, it has been established that increasing the coupling radius allows to enhance the effect of coherence resonance which is reflected in the evolution of the dependence of the correlation time on the noise intensity and the power spectrum transformations. Nonlocal coupling is considered as an intermediate option between local and global coupling topologies which are also discussed as a tool for controlling coherence resonance.
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Discretisation and independent resolutions of ample groupoids
Xin Li, Alistair Miller
https://arxiv.org/abs/2606.21761 https://arxiv.org/pdf/2606.21761 https://arxiv.org/html/2606.21761
arXiv:2606.21761v1 Announce Type: new
Abstract: We develop a general framework for understanding and computing both the groupoid homology of an ample groupoid and the topological K-theory of its reduced C*-algebra, based on two main ideas: discretisation and independent resolutions. Discretisation shows that a special class of ample groupoids we term independent groupoids are homologically and K-theoretically equivalent to discrete groupoids. We introduce the notion of a resolution by independent groupoids and provide a recipe for building a controlled independent resolution of a given ample groupoid of interest, leading to a systematic way of studying its homology and K-theory. In order to illustrate our general ideas and methods, we work out several concrete examples and applications. Garside categories provide a wide range of examples, including higher rank graphs, self-similar groups and spherical Artin-Tits groups. We also present an application to the homology of Stein's groups.
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"New research […] shows that a modified audio clip undetectable by human ears can manipulate a model’s behavior"
"Real-world examples include hiding malicious instructions in online videos, music clips, or voice notes that users query an AI about, or broadcasting malicious audio on a Zoom call that is then uploaded to AI transcription services."
I expect people will be having fun building 21st century equivalents of the TV-be-gone.

#Cache Stampede Prevention: Distributed Locking, Pub/Sub, and Request Coalescing
https://engineeringatscale.substack.com/p/cache-stampede-distributed-locking…