# gst: black swan ... or black rabbit?

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In his book The Black Swan: The Impact of the Highly Improbable, Nassim Nicholas Taleb explores the profound and unpredictable events that shape our world, which he calls “Black Swans.” These events are characterized by three main features: they are rare and unpredictable, they have an extreme impact, and in hindsight, they often seem explainable or inevitable. Taleb argues that our world is increasingly shaped by these Black Swans, from financial crises to technological breakthroughs, and yet humans are inherently ill equipped to anticipate them due to cognitive biases and reliance on standard predictive models. By analogy with this term, (AA) have named Black Rabbits events that exhibit all the external characteristics of a Black Swan but are entirely determined by the state of the system itself. These phenomena are not artificial examples or mere curiosities; they exist wherever hyperbolic meadows are found. When we witness a social catastrophe or a financial crisis, could it be not a stray Black Swan but a local Black Rabbit? How can one determine in advance that a system is pregnant with a crisis? What indicators can be used? Is it possible to control the system to prevent it from becoming unstable? These are intriguing questions, perhaps too complex, especially when dealing not with simple mathematical models but with real-world systems. Yet, we must still strive to find answers to them.

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Alexey Solyanik. The Black Rabbits of Fibonacci. arXiv: 2412.20222v1 [math.DS]. Dec 28, 2024.

https://arxiv.org/abs/2412.20222

Also: gst - general system theory, analogy, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, analogy

# life: a bizarre 'aleatorio torneamento' revisited; Mickey Mouse (et al.) collapsed, by Ann

<< nelle gronde d' estremo tono dal ristagno d' eterno memento ... //

(..)

tr'astratti lamenti dallo sciamante stenotermo sognante tremore // >>

Aleatorio torneamento. Notes. (quasi-stochastic poetry). Feb 09, 2006.

https://inkpi.blogspot.com/2006/02/1955-aleatorio-torneamento.html 

<< Ann Telnaes, a long-time Washington Post cartoonist, created a cartoon of Mr Bezos and other tycoons kneeling before a statue of President-elect Donald Trump. >>

<< In the cartoon, Mr Bezos, Meta founder Mark Zuckerberg and OpenAI's Sam Altman are depicted on their knees giving bags of cash to a statue of Trump.

Mickey Mouse is also depicted prostrate in the cartoon. ABC News – which is owned by Disney – last month agreed to pay $15m to settle a defamation lawsuit filed by Trump. >>

Ana Faguy. Washington Post cartoonist quits after Bezos satire is rejected. Jan 4, 2025. https://www.bbc.com/news/articles/cn4xk4y2emro  

Ann Telnaes. Why I'm quitting the Washington Post. Jan 4, 2025. 

https://anntelnaes.substack.com/p/why-im-quitting-the-washington-post     https://anntelnaes.com     https://x.com/AnnTelnaes     https://en.m.wikipedia.org/wiki/Ann_Telnaes

Also: Mr. Donald, in https://www.inkgmr.net/kwrds.html 

Keywords: life, Donald, Potus, Potus race

# gst: floating droplets excited with Faraday waves

<< The Faraday instability has been extensively studied in bounded containers but only recently has research on this phenomenon in flexible domains been conducted. (AA) study floating liquid droplets with Faraday waves excited on their surface, which undergo a slow time evolution toward a stable noncircular shape. (AA) develop a theoretical model for the evolution of the boundary of the droplet, thus allowing to simulate its full transient motion toward steady state. >>

<< By changing the forcing frequency and amplitude of (the) system, (They) observe a variety of stable droplet shapes. (..) Interesting transient behavior such as hysteresis is also discussed, where the final droplet shape depends on its previous shape. Finally, (They) touch upon droplets that do not reach a steady state shape, instead oscillating periodically in time or rotating at a constant angular velocity. >>️

L. Mazereeuw. Theoretical and experimental investigation of the shapes formed by floating droplets excited with Faraday waves. Phys. Rev. Fluids 9, 124404. Dec 19, 2024.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.124404

Also: drop, waves, instability, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: drops, droplets, droploids, waves, instability, Faraday instability, transitions   

# gst: soliton dynamics over a disordered topography

AA << report on the dynamics of a soliton propagating on the surface of a fluid in a 4-m-long canal with a random or periodic bottom topography. Using a full space-and-time resolved wave field measurement, (They) evidence, for the first time experimentally, how the soliton is affected by the disorder, in the context of Anderson localization, and how localization depends on nonlinearity. >>

<< For weak soliton amplitudes, the localization length is found in quantitative agreement with a linear shallow-water theory. For higher amplitudes, this spatial attenuation of the soliton amplitude is found to be enhanced. >>

<< Behind the leading soliton slowed down by the topography, different experimentally unreported dynamics occur: fission into backward and forward nondispersive pulses for the periodic case, and scattering into dispersive waves for the random case. >>

Guillaume Ricard, Eric Falcon. Soliton Dynamics over a Disordered Topography. Phys. Rev. Lett. 133, 264002. Dec 27, 2024.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.264002

Also: soliton, waves, disorder, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, soliton, waves, disorder

# gst: self-organized critical dynamic on the Sierpinski carpet.

<< Self-organized criticality is a dynamical system property where, without external tuning, a system naturally evolves towards its critical state, characterized by scale-invariant patterns and power-law distributions.  >>️

In this paper, AA << explored a self-organized critical dynamic on the Sierpinski carpet lattice, a scale-invariant structure whose dimension is defined as a power law with a noninteger exponent, i.e., a fractal. To achieve this, (They) proposed an Ising–bond-correlated percolation model as the foundation for investigating critical dynamics.  >>️

<< Within this framework, (AA) outlined a feedback mechanism for critical self-organization and followed an algorithm for its numerical implementation. The results obtained from the algorithm demonstrated enhanced efficiency when driving the Sierpinski carpet towards critical self-organization compared to a two-dimensional lattice.  >>️

Viviana Gomez, Gabriel Tellez. Self-organized critical dynamic on the Sierpinski carpet. Phys. Rev. E 110, 064141. Dec 20, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.064141 

Also: self-assembly, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, self-assembly, criticality, self-organized critical dynamics, transitions.

# gst: stochastic adaptation, stochastic resonance.

<< Stochastic resonance is a phenomenon possessed by some nonlinear oscillators, in which a weak signal is boosted by noise. Both the monostable and bistable Duffing oscillators can exhibit this property. However, stochastic resonance has a strong frequency-dependence, as only a band of frequencies may be boosted by noise. >>️

<< Adaptive oscillators are a subset of nonlinear oscillators that can learn the features of an external force. (In this AA work), an adaptive state is added to a Duffing oscillator. This adaptive state enables the Duffing adaptive oscillator to outperform stochastic resonance over a wide range of frequencies by learning a resonance condition. >>️

Edmon Perkins. Comparison of stochastic adaptation and stochastic resonance. Phys. Rev. E 110, 064225. Dec 27, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.064225 

Also: fluctuations, noise, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, fluctuations, noise, transition, stochasticity, stochastic adaptation, stochastic resonance

# gst: nascent water waves induced by the impulsive motion of a solid wall; an unsteady hydraulic jump theory

Fig. 2: Representative cases of the different regimes of impulse waves observed: (a) dispersive wave; (b) solitary-like wave; (c) plunging breaking bore; (d) water jet 

AA << investigated the generation phase of laboratory-scale water waves induced by the impulsive motion of a rigid piston, whose maximum velocity U and total stroke L are independently varied, as well as the initial liquid depth h. By doing so, the influence of two dimensionless numbers is studied: the Froude number Frp (..), with g the gravitational acceleration, and the relative stroke Λp (..) of the piston. >>️

<< For large Froude numbers, an unsteady hydraulic jump theory is proposed, which accurately predicts the time evolution of the wave amplitude at the contact with the piston throughout the generation phase. At the end of the formation process, the dimensionless volume of the bump evolves linearly with Λp and the wave aspect ratio is found to be governed by the relative acceleration γ/g. As the piston begins its constant deceleration, the water bump evolves into a propagating wave and several regimes (such as dispersive, solitary-like and bore waves, as well as water jets) are then reported and mapped in a phase diagram in the (Frp, Λp) plane. While the transition from waves to water jets is observed if the typical acceleration of the piston is close enough to the gravitational acceleration g, the wave regimes are found to be mainly selected by the relative piston stroke Λp while the Froude number determines whether the generated wave breaks or not. >>️

️

Wladimir Sarlin, Zhaodong Niu, et al. Nascent water waves induced by the impulsive motion of a solid wall. arXiv: 2412.08216v1 [physics.flu-dyn]. Dec 11, 2024. 

https://arxiv.org/abs/2412.08216

Also: waves, soliton, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, soliton