18,588 research outputs found
A Model of Two-Dimensional Quantum Gravity in the Strong Coupling Regime
A model of two-dimensional quantum gravity that is the analog of the
tensionless string is proposed. The gravitational constant () is the analog
of the Regge slope () and it shows that when , quantum gravity can be understood as a tensionless string theory
embeded in a two-dimensional target space. The temporal coordinate of the
target space play the role of time and the wave function can be interpreted as
in standard quantum mechanics.Comment: 10pp., Revtex, Si/94/0
Quantum Mechanics on Multiply Connected Manifolds with Applications to One and Two Dimensional Anyons
In these lectures several aspects of anyon in one and two dimensions are
considered from the path integral formalism. This paper is based in a set of
four lectures given by the author in the "V Latinoamerican Workshop of
Particles and Fields, hel in Puebla, Mexico.Comment: 27pp, Late
Static plane symmetric relativistic fluids and empty repelling singular boundaries
We present a detailed analysis of the general exact solution of Einstein's
equation corresponding to a static and plane symmetric distribution of matter
with density proportional to pressure. We study the geodesics in it and we show
that this simple spacetime exhibits very curious properties. In particular, it
has a free of matter repelling singular boundary and all geodesics bounce off
it.Comment: 9 pages, 1 figure, accepted for publication in Classical and Quantum
Gravit
Large Deviations for Random Spectral Measures and Sum Rules
We prove a Large Deviation Principle for the random spec- tral measure
associated to the pair where is sampled in the GUE(N) and e is
a fixed unit vector (and more generally in the - extension of this
model). The rate function consists of two parts. The contribution of the
absolutely continuous part of the measure is the reversed Kullback information
with respect to the semicircle distribution and the contribution of the
singular part is connected to the rate function of the extreme eigenvalue in
the GUE. This method is also applied to the Laguerre and Jacobi ensembles, but
in thoses cases the expression of the rate function is not so explicit
Conditional Transfers to Promote Local Government Participation in Mexico
Mexico is a very centralized country mainly as a result of the involvement of the federal government (FG) in functions that would be more efficiently provided by subnational governments (SG). The concentration of activities in the FG is the result of two institutional features: the unclear legal assignment of expenditure functions across levels of government, and the assignment of sources of revenue that concentrates a larger share of revenues in hands of the FG. In the presence of multiple uses of federal transfers, and in the absence of information on the costs of providing SG services, the FG has been reasonably reluctant to decentralize more functions. As long as the FG remains in control of most of government revenues, it is important to ensure that the benefits from decentralization also accrue to it. The transfer of functions should avoid SG neglect of those functions that generate benefits to the rest of the country and keep control over the size of transfers. One instrument that can achieve both objectives is a widespread use of conditional grants.
Perfect Numbers in ACL2
A perfect number is a positive integer n such that n equals the sum of all
positive integer divisors of n that are less than n. That is, although n is a
divisor of n, n is excluded from this sum. Thus 6 = 1 + 2 + 3 is perfect, but
12 < 1 + 2 + 3 + 4 + 6 is not perfect. An ACL2 theory of perfect numbers is
developed and used to prove, in ACL2(r), this bit of mathematical folklore:
Even if there are infinitely many perfect numbers the series of the reciprocals
of all perfect numbers converges.Comment: In Proceedings ACL2 2015, arXiv:1509.0552
Equivalence of the Traditional and Non-Standard Definitions of Concepts from Real Analysis
ACL2(r) is a variant of ACL2 that supports the irrational real and complex
numbers. Its logical foundation is based on internal set theory (IST), an
axiomatic formalization of non-standard analysis (NSA). Familiar ideas from
analysis, such as continuity, differentiability, and integrability, are defined
quite differently in NSA-some would argue the NSA definitions are more
intuitive. In previous work, we have adopted the NSA definitions in ACL2(r),
and simply taken as granted that these are equivalent to the traditional
analysis notions, e.g., to the familiar epsilon-delta definitions. However, we
argue in this paper that there are circumstances when the more traditional
definitions are advantageous in the setting of ACL2(r), precisely because the
traditional notions are classical, so they are unencumbered by IST limitations
on inference rules such as induction or the use of pseudo-lambda terms in
functional instantiation. To address this concern, we describe a formal proof
in ACL2(r) of the equivalence of the traditional and non-standards definitions
of these notions.Comment: In Proceedings ACL2 2014, arXiv:1406.123
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