2,455 research outputs found
Extreme value laws for fractal intensity functions in dynamical systems: Minkowski analysis
Typically, in the dynamical theory of extremal events, the function that
gauges the intensity of a phenomenon is assumed to be convex and maximal, or
singular, at a single, or at most a finite collection of points in
phase--space. In this paper we generalize this situation to fractal landscapes,
i.e. intensity functions characterized by an uncountable set of singularities,
located on a Cantor set. This reveals the dynamical r\^ole of classical
quantities like the Minkowski dimension and content, whose definition we extend
to account for singular continuous invariant measures. We also introduce the
concept of extremely rare event, quantified by non--standard Minkowski
constants and we study its consequences to extreme value statistics. Limit laws
are derived from formal calculations and are verified by numerical experiments.Comment: 20 pages, 13 figure
Universality classes for horizon instabilities
We introduce a notion of universality classes for the Gregory-Laflamme
instability and determine, in the supergravity approximation, the stability of
a variety of solutions, including the non-extremal D3-brane, M2-brane, and
M5-brane. These three non-dilatonic branes cross over from instability to
stability at a certain non-extremal mass. Numerical analysis suggests that the
wavelength of the shortest unstable mode diverges as one approaches the
cross-over point from above, with a simple critical exponent which is the same
in all three cases.Comment: 23 pages, latex2e, 4 figure
Bounds for avalanche critical values of the Bak-Sneppen model
We study the Bak-Sneppen model on locally finite transitive graphs , in
particular on Z^d and on T_Delta, the regular tree with common degree Delta. We
show that the avalanches of the Bak-Sneppen model dominate independent site
percolation, in a sense to be made precise. Since avalanches of the Bak-Sneppen
model are dominated by a simple branching process, this yields upper and lower
bounds for the so-called avalanche critical value . Our main
results imply that 1/(Delta+1) <= \leq p_c^{BS}(T_Delta) \leq 1/(Delta -1)1/(2d+1)\leq p_c^{BS}(Z^d)\leq 1/(2d)+ 1/(2d)^2+O(d^{-3}), as
d\to\infty.Comment: 19 page
Multiparty Dynamics and Failure Modes for Machine Learning and Artificial Intelligence
An important challenge for safety in machine learning and artificial
intelligence systems is a~set of related failures involving specification
gaming, reward hacking, fragility to distributional shifts, and Goodhart's or
Campbell's law. This paper presents additional failure modes for interactions
within multi-agent systems that are closely related. These multi-agent failure
modes are more complex, more problematic, and less well understood than the
single-agent case, and are also already occurring, largely unnoticed. After
motivating the discussion with examples from poker-playing artificial
intelligence (AI), the paper explains why these failure modes are in some
senses unavoidable. Following this, the paper categorizes failure modes,
provides definitions, and cites examples for each of the modes: accidental
steering, coordination failures, adversarial misalignment, input spoofing and
filtering, and goal co-option or direct hacking. The paper then discusses how
extant literature on multi-agent AI fails to address these failure modes, and
identifies work which may be useful for the mitigation of these failure modes.Comment: 12 Pages, This version re-submitted to Big Data and Cognitive
Computing, Special Issue "Artificial Superintelligence: Coordination &
Strategy
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