1,519 research outputs found
Causal inference using the algorithmic Markov condition
Inferring the causal structure that links n observables is usually based upon
detecting statistical dependences and choosing simple graphs that make the
joint measure Markovian. Here we argue why causal inference is also possible
when only single observations are present.
We develop a theory how to generate causal graphs explaining similarities
between single objects. To this end, we replace the notion of conditional
stochastic independence in the causal Markov condition with the vanishing of
conditional algorithmic mutual information and describe the corresponding
causal inference rules.
We explain why a consistent reformulation of causal inference in terms of
algorithmic complexity implies a new inference principle that takes into
account also the complexity of conditional probability densities, making it
possible to select among Markov equivalent causal graphs. This insight provides
a theoretical foundation of a heuristic principle proposed in earlier work.
We also discuss how to replace Kolmogorov complexity with decidable
complexity criteria. This can be seen as an algorithmic analog of replacing the
empirically undecidable question of statistical independence with practical
independence tests that are based on implicit or explicit assumptions on the
underlying distribution.Comment: 16 figure
Kolmogorov Complexity, Cosmic Background Radiation and Irreversibility
We discuss the algorithmic information approach to the analysis of the
observational data on the Universe. Kolmogorov complexity is proposed as a
descriptor of the Cosmic Microwave Background (CMB) radiation maps. An
algorithm of computation of the complexity is described, applied, first, to toy
models and then, to the data of the Boomerang experiment. The sky maps obtained
via the summing of two independent Boomerang channels reveal threshold
independent behavior of the mean ellipticity of the anisotropies, thus
indicating correlations present in the sky signal and possibly carrying crucial
information on the curvature and the non-Friedmannian, i.e. accelerated
expansion of the Universe. Similar effect has been detected for COBE-DMR 4 year
maps. Finally, as another application of these concepts, we consider the
possible link between the CMB properties, curvature of the Universe and arrows
of time.Comment: Talk at XXII Solvay Conference on Physics "The Physics of
Communication" (Delphi, November 24-29, 2001); the discussion include
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