276 research outputs found
An adjunction formula for the Emerton-Jacquet functor
The Emerton–Jacquet functor is a tool for studying locally analytic representations of p-adic Lie groups. It provides a way to access the theory of p-adic automorphic forms. Here we give an adjunction formula for the Emerton–Jacquet functor, relating it directly to locally analytic inductions, under a strict hypothesis that we call non-critical. We also further study the relationship to socles of principal series in the non-critical setting
Análisis filogenético de aislamientos de Groundnut ringspot virus desde maní e identificación de posibles trips vectores asociados al cultivo de maní en la Argentina
Groundnut ringspot virus (GRSV), genus Tospovirus, is a thrips-transmitted virus infecting peanuts (Arachis hypogaea L.) in Córdoba province, Argentina. Fourteen viral isolates were recovered from Tospovirus-like symptomatic plants from different peanut fields. Viral isolates as GRSV were identified by serological and molecular tests. Nucleotide and derived amino acid sequence analyses of the nucleocapsid (N) gene indicated a high degree of identity between the GRSV peanut isolates, indicating that there is no molecular variability in the N gene of the GRSV that infects peanuts in the cropping area of Córdoba. In this study, we determined the presence of thrips species in the crop, which can potentially transmit the virus. Thrips were observed in all the evaluated peanut fields. Frankliniella schultzei was the most frequently identified species followed by Caliothrips phaseoli and Frankliniella occidentalis. This work reports the presence of F. schultzei and F. occidentalis in peanuts in Argentina for the first time. These results along with the high degree of similarity between the GRSV peanut isolates suggest that the virus could be transmitted by F. schultzei, which has been cited as its most efficient vector.Groundnut ringspot virus (GRSV, género Tospovirus) es un virus que infecta naturalmente el cultivo de maní (Arachis hypogaea L.) en la región productora de Córdoba, Argentina. En distintas localidades de la provincia, se colectaron 14 aislamientos virales provenientes de maníes que manifestaban síntomas característicos de Tospovirus. Todos los aislamientos virales fueron identificados como GRSV mediante pruebas serológicas y moleculares. El análisis de las secuencias nucleotídicas y de amino ácidos deducidas del gen de la nucleoproteína (N) reveló un alto grado de identidad entre los 14 aislamientos, indicando que no existe variabilidad molecular en el gen N del GRSV que infecta maní en la provincia de Córdoba. En este estudio se determinó la presencia de trips en el cultivo que pueden potencialmente transmitir la enfermedad. Estos insectos fueron observados colonizando maní en todos los lotes evaluados. La especie identificada con mayor frecuencia fue Frankliniella schultzei, seguida de Caliothrips phaseoli y Frankliniella occidentalis. Este es el primer reporte de F. schultzei y F. occidentalis afectando maní en Argentina. Estos resultados, junto con el elevado grado de similitud encontrado entre los distintos aislamientos de GRSV, sugieren que el virus puede ser transmitido por F. schultzei, citado como el vector más eficiente del GRSV
The classification of irreducible admissible mod p representations of a p-adic GL_n
Let F be a finite extension of Q_p. Using the mod p Satake transform, we
define what it means for an irreducible admissible smooth representation of an
F-split p-adic reductive group over \bar F_p to be supersingular. We then give
the classification of irreducible admissible smooth GL_n(F)-representations
over \bar F_p in terms of supersingular representations. As a consequence we
deduce that supersingular is the same as supercuspidal. These results
generalise the work of Barthel-Livne for n = 2. For general split reductive
groups we obtain similar results under stronger hypotheses.Comment: 55 pages, to appear in Inventiones Mathematica
Color Improves Edge Classification
Meeting AbstractCopyright 2019 The Author(s). Our visual environment contains both luminance and color (chromatic) information. Understanding the role that each plays in our visual perception of natural scenes is a continuing topic of investigation. In this study, we explore the role that color cues play in a specific task: edge classification. Despite the complexity of the visual world, humans rarely confuse variations in illumination, for example, shadows, from variations in material properties, for example, paint or stain. This ability to distinguish illumination from material edges is crucial for determining the spatial layout of objects and surfaces in natural scenes. Color is believed to be a useful cue to this categorization, given that most color changes tend to be material in origin, whereas luminance changes tend to be either material or illumination in origin. We conducted a psychophysical experiment that required subjects to classify edges as “shadow” or “other,” for images containing or not color information. We found edge classification performance to be superior for the color compared with grayscale images. We also defined machine observers sensitive to simple image properties and found that they too classified the edges better with color information. Our results show that color acts as a cue for edge classification in images of natural scenes
Color improves edge classification in human vision
Data Availability Statement: All relevant data are within the manuscript and its Supporting Information files.© 2019 Breuil et al. Despite the complexity of the visual world, humans rarely confuse variations in illumination, for example shadows, from variations in material properties, such as paint or stain. This ability to distinguish illumination from material edges is crucial for determining the spatial layout of objects and surfaces in natural scenes. In this study, we explore the role that color (chromatic) cues play in edge classification. We conducted a psychophysical experiment that required subjects to classify edges into illumination and material, in patches taken from images of natural scenes that either contained or did not contain color information. The edge images were of various sizes and were pre-classified into illumination and material, based on inspection of the edge in the context of the whole image from which the edge was extracted. Edge classification performance was found to be superior for the color compared to grayscale images, in keeping with color acting as a cue for edge classification. We defined machine observers sensitive to simple image properties and found that they too classified the edges better with color information, although they failed to capture the effect of image size observed in the psychophysical experiment. Our findings are consistent with previous work suggesting that color information facilitates the identification of material properties, transparency, shadows and the perception of shape-from-shading.IDEX; Canadian Institute of Health. The study was supported by a travel grant from IDEX given to CB and a Canadian Institute of Health Research grant #MOP 123349 given to FK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
The Tate conjecture for K3 surfaces over finite fields
Artin's conjecture states that supersingular K3 surfaces over finite fields
have Picard number 22. In this paper, we prove Artin's conjecture over fields
of characteristic p>3. This implies Tate's conjecture for K3 surfaces over
finite fields of characteristic p>3. Our results also yield the Tate conjecture
for divisors on certain holomorphic symplectic varieties over finite fields,
with some restrictions on the characteristic. As a consequence, we prove the
Tate conjecture for cycles of codimension 2 on cubic fourfolds over finite
fields of characteristic p>3.Comment: 20 pages, minor changes. Theorem 4 is stated in greater generality,
but proofs don't change. Comments still welcom
Eisenstein Series of Weight One, q-Averages of the 0-Logarithm and Periods of Elliptic Curves
For any elliptic curve E over k ⊂ R with E(C) = C^×/q^Z, q = e^(2πiz),Im(z) >, we study the q-average D_(0,q), defined on E(C), of the function D_0(z) = Im(z/(1−z)). Let Ω+(E) denote the real period of E. We show that there is a rational function R ∈ Q(X_1(N)) such that for any non-cuspidal real point s ∈ X_1(N) (which defines an elliptic curve E(s) over R together with a point P(s) of order N), πD_(0,q)(P(s)) equals Ω+(E(s))R(s). In particular, if s is Q-rational point of X_1(N), a rare occurrence according to Mazur, R(s) is a rational number
Galois sections for abelianized fundamental groups
Given a smooth projective curve of genus at least 2 over a number field
, Grothendieck's Section Conjecture predicts that the canonical projection
from the \'etale fundamental group of onto the absolute Galois group of
has a section if and only if the curve has a rational point. We show that there
exist curves where the above map has a section over each completion of but
not over . In the appendix Victor Flynn gives explicit examples in genus 2.
Our result is a consequence of a more general investigation of the existence
of sections for the projection of the \'etale fundamental group `with
abelianized geometric part' onto the Galois group. We give a criterion for the
existence of sections in arbitrary dimension and over arbitrary perfect fields,
and then study the case of curves over local and global fields more closely. We
also point out the relation to the elementary obstruction of
Colliot-Th\'el\`ene and Sansuc.Comment: This is the published version, except for a characteristic 0
assumption added in Section 5 which was unfortunately omitted there. Thanks
to O. Wittenberg for noticing i
On a Conjecture of Rapoport and Zink
In their book Rapoport and Zink constructed rigid analytic period spaces
for Fontaine's filtered isocrystals, and period morphisms from PEL
moduli spaces of -divisible groups to some of these period spaces. They
conjectured the existence of an \'etale bijective morphism of
rigid analytic spaces and of a universal local system of -vector spaces on
. For Hodge-Tate weights and we construct in this article an
intrinsic Berkovich open subspace of and the universal local
system on . We conjecture that the rigid-analytic space associated with
is the maximal possible , and that is connected. We give
evidence for these conjectures and we show that for those period spaces
possessing PEL period morphisms, equals the image of the period morphism.
Then our local system is the rational Tate module of the universal
-divisible group and enjoys additional functoriality properties. We show
that only in exceptional cases equals all of and when the
Shimura group is we determine all these cases.Comment: v2: 48 pages; many new results added, v3: final version that will
appear in Inventiones Mathematica
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Terrestrial implications for the maritime geoarchaeological resource: A view from the Lower Palaeolithic
Stone tools and faunal remains have been recovered from the English Channel and the North Sea through trawling, dredging for aggregates, channel clearance, and coring. These finds highlight the potential for a maritime Lower Palaeolithic archaeological resource. It is proposed here that any Lower Palaeolithic artefacts, faunal remains, and sediments deposited in the maritime zone during dry, low-stand phases were once (and may still be) contextually similar to their counterparts in the terrestrial Lower Palaeolithic records of north-western Europe. Given these similarities, can interpretive models and analytical frameworks developed for terrestrial archaeology be profitably applied to an assessment of the potential value of any maritime resource? The terrestrial geoarchaeological resource for the Lower Palaeolithic is dominated by artefacts and ecofacts that have been fluvially reworked. The spatio-temporal resolution of these data varies from entire river valleys and marine isotope stages to river channel gravel bar surfaces and decadal timescales, thus supporting a variety of questions and approaches. However, the structure of the terrestrial resource also highlights two fundamental limitations in current maritime knowledge that can restrict the application of terrestrial approaches to any potential maritime resource: (i) how have the repetitive transgressions and regressions of the Middle and Late Pleistocene modified the terrace landforms and sediments associated with the river systems of the English Channel and southern North Sea basins?; and (ii) do the surviving submerged terrace landforms and fluvial sedimentary deposits support robust geochronological models, as is the case with the classical terrestrial terrace sequences? This paper highlights potential approaches to these questions, and concludes that the fluvial palaeogeography, Pleistocene fossils, and potential Lower Palaeolithic artefacts of the maritime geoarchaeological resource can be profitably investigated in future as derived, low-resolution data sets, facilitating questions of colonisation, occupation, demography, and material culture
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