15,259 research outputs found
Algorithmic Randomness as Foundation of Inductive Reasoning and Artificial Intelligence
This article is a brief personal account of the past, present, and future of
algorithmic randomness, emphasizing its role in inductive inference and
artificial intelligence. It is written for a general audience interested in
science and philosophy. Intuitively, randomness is a lack of order or
predictability. If randomness is the opposite of determinism, then algorithmic
randomness is the opposite of computability. Besides many other things, these
concepts have been used to quantify Ockham's razor, solve the induction
problem, and define intelligence.Comment: 9 LaTeX page
Mesoscopic Mechanics
This article is concerned with the existence, status and description of the
so-called emergent phenomena believed to occur in certain principally planar
electronic systems. In fact, two distinctly different if inseparable tasks are
accomplished. First, a rigorous mathematical model is proposed of emergent
character, which is conceptually bonded with Quantum Mechanics while apparently
non-derivable from the many-body Schr\"{o}dinger equation. I call the resulting
conceptual framework the Mesoscopic Mechanics (MeM). Its formulation is
space-independent and comprises a nonlinear and holistic extension of the free
electron model. Secondly, the question of relevancy of the proposed ``emergent
mechanics" to the actually observed phenomena is discussed. In particular, I
postulate a probabilistic interpretation, and indicate how the theory could be
applied and verified by experiment.
The Mesoscopic Mechanics proposed here has been deduced from the Nonlinear
Maxwell Theory (NMT)--a classical in character nonlinear field theory. This
latter theory has already been shown to provide a consistent phenomenological
model of such phenomena as superconductivity, charge stripes, magnetic vortex
lattice, and magnetic oscillations. The NMT, which arose from geometric
considerations, has long been awaiting an explanation as to its ties with the
fundamental principles. I believe the MeM provides at least a partial
explanation to this effect.Comment: 20 pages, 2 figure
Proving Quadratic Reciprocity: Explanation, Disagreement, Transparency and Depth
Gauss’s quadratic reciprocity theorem is among the most important results in the history of number theory. It’s also among the most mysterious: since its discovery in the late 18th century, mathematicians have regarded reciprocity as a deeply surprising fact in need of explanation. Intriguingly, though, there’s little agreement on how the theorem is best explained. Two quite different kinds of proof are most often praised as explanatory: an elementary argument that gives the theorem an intuitive geometric interpretation, due to Gauss and Eisenstein, and a sophisticated proof using algebraic number theory, due to Hilbert. Philosophers have yet to look carefully at such explanatory disagreements in mathematics. I do so here. According to the view I defend, there are two important explanatory virtues—depth and transparency—which different proofs (and other potential explanations) possess to different degrees. Although not mutually exclusive in principle, the packages of features associated with the two stand in some tension with one another, so that very deep explanations are rarely transparent, and vice versa. After developing the theory of depth and transparency and applying it to the case of quadratic reciprocity, I draw some morals about the nature of mathematical explanation
Euclid's theorem on the infinitude of primes: a historical survey of its proofs (300 B.C.--2017) and another new proof
In this article, we provide a comprehensive historical survey of 183
different proofs of famous Euclid's theorem on the infinitude of prime numbers.
The author is trying to collect almost all the known proofs on infinitude of
primes, including some proofs that can be easily obtained as consequences of
some known problems or divisibility properties. Furthermore, here are listed
numerous elementary proofs of the infinitude of primes in different arithmetic
progressions.
All the references concerning the proofs of Euclid's theorem that use similar
methods and ideas are exposed subsequently. Namely, presented proofs are
divided into 8 subsections of Section 2 in dependence of the methods that are
used in them. {\bf Related new 14 proofs (2012-2017) are given in the last
subsection of Section 2.} In the next section, we survey mainly elementary
proofs of the infinitude of primes in different arithmetic progressions.
Presented proofs are special cases of Dirichlet's theorem. In Section 4, we
give a new simple "Euclidean's proof" of the infinitude of primes.Comment: 70 pages. In this extended third version of the article, 14 new
proofs of the infnitude of primes are added (2012-2017
Superfilters, Ramsey theory, and van der Waerden's Theorem
Superfilters are generalized ultrafilters, which capture the underlying
concept in Ramsey theoretic theorems such as van der Waerden's Theorem. We
establish several properties of superfilters, which generalize both Ramsey's
Theorem and its variant for ultrafilters on the natural numbers. We use them to
confirm a conjecture of Ko\v{c}inac and Di Maio, which is a generalization of a
Ramsey theoretic result of Scheepers, concerning selections from open covers.
Following Bergelson and Hindman's 1989 Theorem, we present a new simultaneous
generalization of the theorems of Ramsey, van der Waerden, Schur,
Folkman-Rado-Sanders, Rado, and others, where the colored sets can be much
smaller than the full set of natural numbers.Comment: Among other things, the results of this paper imply (using its
one-dimensional version) a higher-dimensional version of the Green-Tao
Theorem on arithmetic progressions in the primes. The bibliography is now
update
Finitary and Infinitary Mathematics, the Possibility of Possibilities and the Definition of Probabilities
Some relations between physics and finitary and infinitary mathematics are
explored in the context of a many-minds interpretation of quantum theory. The
analogy between mathematical ``existence'' and physical ``existence'' is
considered from the point of view of philosophical idealism. Some of the ways
in which infinitary mathematics arises in modern mathematical physics are
discussed. Empirical science has led to the mathematics of quantum theory. This
in turn can be taken to suggest a picture of reality involving possible minds
and the physical laws which determine their probabilities. In this picture,
finitary and infinitary mathematics play separate roles. It is argued that
mind, language, and finitary mathematics have similar prerequisites, in that
each depends on the possibility of possibilities. The infinite, on the other
hand, can be described but never experienced, and yet it seems that sets of
possibilities and the physical laws which define their probabilities can be
described most simply in terms of infinitary mathematics.Comment: 21 pages, plain TeX, related papers from
http://www.poco.phy.cam.ac.uk/~mjd101
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