2,342 research outputs found
The Budget-Constrained Functional Dependency
Armstrong's axioms of functional dependency form a well-known logical system
that captures properties of functional dependencies between sets of database
attributes. This article assumes that there are costs associated with
attributes and proposes an extension of Armstrong's system for reasoning about
budget-constrained functional dependencies in such a setting.
The main technical result of this article is the completeness theorem for the
proposed logical system. Although the proposed axioms are obtained by just
adding cost subscript to the original Armstrong's axioms, the proof of the
completeness for the proposed system is significantly more complicated than
that for the Armstrong's system
The Fermion Generations Problem in the Gust in the Free World-Sheet Fermion Formulation
In the framework of the four dimensional heterotic superstring with free
fermions we present a revised version of the rank eight Grand Unified String
Theories (GUST) which contain the -gauge family symmetry. We also
develop some methods for building of corresponding string models. We explicitly
construct GUST with gauge symmetry and or
and consider the full massless spectrum for our string models.
We consider for the observable gauge symmetry the diagonal subgroup
of the rank 16 group or . We discuss the possible fermion matter and Higgs sectors in
these theories. We study renormalizable and nonrenormolizable contributions to
the superpotential. There has to exist "superweak" light chiral matter () in GUST under consideration. The understanding of quark and lepton mass
spectra and family mixing leaves a possibility for the existence of an
unusually low mass breaking scale of the family gauge symmetry (some
TeV).Comment: 68 page
The Paths of Unification In The GUST With The G x G Gauge Groups of E(8) x E(8)
In the framework of the four dimensional heterotic superstring with free
fermions we discuss the rank eight and/or sixteen Grand Unified String Theories
(GUST) which contain the SU(3)_H - gauge family symmetry. We explicitly
investigate the paths of the unification in the GUST with gauge symmetry G x G
= [SU(5) x U(1) x (SU(3) x U(1))_H]^2. We show that the GUSTs with the G x G
gauge group allow to make the scale of unification to be consistent with the
string scale M_SU = g_{string} * 5 * 10^17 GeV.Comment: 18 pages, 2 Postscript figures, uses epsf.st
Topological phase in two flavor neutrino oscillations
We show that the phase appearing in neutrino flavor oscillation formulae has
a geometric and topological contribution. We identify a topological phase
appearing in the two flavor neutrino oscillation formula using Pancharatnam's
prescription of quantum collapses between non-orthogonal states. Such quantum
collapses appear naturally in the expression for appearance and survival
probabilities of neutrinos. Our analysis applies to neutrinos propagating in
vacuum or through matter. For the minimal case of two flavors with CP
conservation, our study shows for the first time that there is a geometric
interpretation of the neutrino oscillation formulae for the detection
probability of neutrino species.Comment: 11 pages, 3 figures, accepted in Phys. Rev.
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