2,327,771 research outputs found
Are there Hilbert-style Pure Type Systems?
For many a natural deduction style logic there is a Hilbert-style logic that
is equivalent to it in that it has the same theorems (i.e. valid judgements
with empty contexts). For intuitionistic logic, the axioms of the equivalent
Hilbert-style logic can be propositions which are also known as the types of
the combinators I, K and S. Hilbert-style versions of illative combinatory
logic have formulations with axioms that are actual type statements for I, K
and S. As pure type systems (PTSs)are, in a sense, equivalent to systems of
illative combinatory logic, it might be thought that Hilbert-style PTSs (HPTSs)
could be based in a similar way. This paper shows that some PTSs have very
trivial equivalent HPTSs, with only the axioms as theorems and that for many
PTSs no equivalent HPTS can exist. Most commonly used PTSs belong to these two
classes. For some PTSs however, including lambda* and the PTS at the basis of
the proof assistant Coq, there is a nontrivial equivalent HPTS, with axioms
that are type statements for I, K and S.Comment: Accepted in Logical Methods in Computer Scienc
The Superposition Principle of Waves Not Fulfilled under M. W. Evans' O(3) Hypothesis
In 1992 M.W. Evans proposed a so-called O(3) symmetry of electromagnetic
fields by adding a constant longitudinal "ghost field" to the well-known
transversal plane em waves. He considered this symmetry as a new law of
electromagnetics. Later on, since 2002, this O(3) symmetry became the center of
his Generally Covariant Unified Field Theory which he recently renamed as ECE
Theory. One of the best-checked laws of electrodynamics is the principle of
linear superposition of electromagnetic waves, manifesting itself in
interference phenomena. Its mathematical equivalent is the representation of
electric and magnetic fields as vectors. By considering the superposition of
two phase-shifted waves we show that the superposition principle is
incompatible with M.W. Evans' O(3) hypothesis.Comment: 5 pages, no figure
On a possibility to determine the S-factor of the hep process in experiments with thermal (cold) neutrons
The problem of the magnitude of the S--factor of the hep process is one of the most important
unsolved problems in nuclear astrophysics. The magnitude of has also
an important impact on the interpretation of the Super-Kamiokande solar
neutrino results in terms of neutrino oscillations. We point out the possiblity
to determine the major hadronic contribution to from the measurement
of the total cross section of the process in experiments with high intensity beams
of thermal or cold neutrons.Comment: 7 pages, revtex, no figures; note added; final version to be
published in Astropart. Phy
Charge asymmetries of lepton transverse momenta in Drell-Yan processes at the LHC
Charged lepton transverse momenta in the Drell-Yan processes play an
important role at the LHC in precision measurements of the Standard Model
parameters, such as the W-boson mass and width, their charge asymmetries and
sin^2(theta_W). Therefore, their distributions should be described as accurate
as possible by the Monte Carlo event generators. In this paper we discuss the
problem of matching the hard-process kinematics of the Monte Carlo generator
WINHAC with the parton-shower kinematics of the PYTHIA 6.4 generator while
interfacing these two programs. We show that improper assignment of the quark
and antiquark effective momenta in the LO matrix element computations may
affect considerably the predicted lepton transverse momenta and even completely
reverse their charge asymmetries at the LHC. We propose two matching schemes in
which the NLO QCD distributions of the leptonic kinematical variables can be
well reproduced by the LO WINHAC generator.Comment: 18 pages, 8 figure
Optimization Techniques for the Power Beaming Analysis of Microwave Transmissions from a Space-Based Solar Power Satellite
In the 21st century, the development of technologies to produce carbon free power sources remains paramount. In this paper, we study an optimal power transmission strategy from a space-based satellite generation station to Earth using scalar diffraction theory. The resulting model is then solved via a spectral method that guarantees a compactly supposed profile from the transmitting antenna. Finally, the problem is then solved via a more general pseudo-spectral method using control theory
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