2,749 research outputs found
Zeta-like Multizeta Values for higher genus curves
We prove or conjecture several relations between the multizeta values for
positive genus function fields of class number one, focusing on the zeta-like
values, namely those whose ratio with the zeta value of the same weight is
rational (or conjecturally equivalently algebraic). These are the first known
relations between multizetas, which are not with prime field coefficients. We
seem to have one universal family. We also find that interestingly the
mechanism with which the relations work is quite different from the rational
function field case, raising interesting questions about the expected motivic
interpretation in higher genus. We provide some data in support of the guesses.Comment: Expository revisions plus appendices containing proofs of more cases
of conjecture
Induction, minimization and collection for Δ n+1 (T)–formulas
For a theory T, we study relationships among IΔ n +1 (T), LΔ n+1 (T) and B * Δ n+1 (T). These theories are obtained restricting the schemes of induction, minimization and (a version of) collection to Δ n+1 (T) formulas. We obtain conditions on T (T is an extension of B * Δ n+1 (T) or Δ n+1 (T) is closed (in T) under bounded quantification) under which IΔ n+1 (T) and LΔ n+1 (T) are equivalent. These conditions depend on Th Πn +2 (T), the Πn+2 –consequences of T. The first condition is connected with descriptions of Th Πn +2 (T) as IΣ n plus a class of nondecreasing total Πn –functions, and the second one is related with the equivalence between Δ n+1 (T)–formulas and bounded formulas (of a language extending the language of Arithmetic). This last property is closely tied to a general version of a well known theorem of R. Parikh. Using what we call Πn –envelopes we give uniform descriptions of the previous classes of nondecreasing total Πn –functions. Πn –envelopes are a generalization of envelopes (see [10]) and are closely related to indicators (see [12]). Finally, we study the hierarchy of theories IΔ n+1 (IΣ m ), m≥n, and prove a hierarchy theorem.Ministerio de Educación y Cultura DGES PB96-134
Risk Assessment Algorithms Based On Recursive Neural Networks
The assessment of highly-risky situations at road intersections have been
recently revealed as an important research topic within the context of the
automotive industry. In this paper we shall introduce a novel approach to
compute risk functions by using a combination of a highly non-linear processing
model in conjunction with a powerful information encoding procedure.
Specifically, the elements of information either static or dynamic that appear
in a road intersection scene are encoded by using directed positional acyclic
labeled graphs. The risk assessment problem is then reformulated in terms of an
inductive learning task carried out by a recursive neural network. Recursive
neural networks are connectionist models capable of solving supervised and
non-supervised learning problems represented by directed ordered acyclic
graphs. The potential of this novel approach is demonstrated through well
predefined scenarios. The major difference of our approach compared to others
is expressed by the fact of learning the structure of the risk. Furthermore,
the combination of a rich information encoding procedure with a generalized
model of dynamical recurrent networks permit us, as we shall demonstrate, a
sophisticated processing of information that we believe as being a first step
for building future advanced intersection safety system
HAWC response to atmospheric electricity activity
The HAWC Gamma Ray observatory consists of 300 water Cherenkov detectors
(WCD) instrumented with four photo multipliers tubes (PMT) per WCD. HAWC is
located between two of the highest mountains in Mexico. The high altitude (4100
m asl), the relatively short distance to the Gulf of Mexico (~100 km), the
large detecting area (22 000 m) and its high sensitivity, make HAWC a good
instrument to explore the acceleration of particles due to the electric fields
existing inside storm clouds. In particular, the scaler system of HAWC records
the output of each one of the 1200 PMTs as well as the 2, 3, and 4-fold
multiplicities (logic AND in a time window of 30 ns) of each WCD with a
sampling rate of 40 Hz. Using the scaler data, we have identified 20
enhancements of the observed rate during periods when storm clouds were over
HAWC but without cloud-earth discharges. These enhancements can be produced by
electrons with energy of tens of MeV, accelerated by the electric fields of
tens of kV/m measured at the site during the storm periods. In this work, we
present the recorded data, the method of analysis and our preliminary
conclusions on the electron acceleration by the electric fields inside the
clouds.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017),
Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution
- …