19 research outputs found
Basi normali intere: risultati principali nel caso generale e sviluppi recenti nel caso abeliano.
Una base normale intera per un'estensione di campi di numeri L/K di Galois è una base dell'anello degli interi di L come modulo sull'anello degli interi di K costituita da elementi coniugati. Trovare una condizione necessaria e sufficiente per l'esistenza di una base normale intera di una data estenisione è un problema aperto. Se L/K è un'estensione di campi locali una condizione necessaria e sufficiente per l'esistenza di una base normale intera è che l'estensione sia tame. Nel caso di campi globali non è noto alcun risultato generale; si sa però che nel caso di estensioni abeliane dei razionali la ramificazione moderata basta a garantire l'esistenza di una tale base. Nell'ultima parte della tesi vengono studiate le estensioni L/K tali che K sia un campo ciclotomico e L un'estensione abeliana dei razionali: viene data una condizione necessaria e sufficiente perché una esista una base normale per queste particolari estensioni e viene definito un indice che misura quanto manca ad una tale estensione all'avere una base normale intera
A crystalline incarnation of Berthelot's conjecture and K\"unneth formula for isocrystals
Berthelot's conjecture predicts that under a proper and smooth morphism of
schemes in characteristic , the higher direct images of an overconvergent
-isocrystal are overconvergent -isocrystals. In this paper we prove that
this is true for crystals up to isogeny. As an application we prove a K\"unneth
formula for the crystalline fundamental group
On -adic differential equations on semistable varieties II
This paper is a complement to the paper "On -adic differential equations
on semistable varieties" written by V. Di Proietto. Given an open variety over
a DVR with semistable reduction, the author constructed in that paper a fully
faithful algebraization functor from the category of certain log overconvergent
isocrystals on the special fiber to the category of modules with regular
integrable connection on the generic fiber. In this paper, we prove that, with
convenable hypothesis, this functor is a tensor functor whose essential image
is closed under extensions and subquotients. As a consequence, we can find
suitable Tannakian subcategories of log overconvergent isocrystals and of
modules with regular integrable connection on which the algebraization functor
is an equivalence of Tannakian categories
Frobenius fixed objects of moduli
Let be a category fibered in groupoids over a finite field
, and let be an algebraically closed field containing
. Denote by the
arithmetic Frobenius of and suppose that is a
stack over (not necessarily in groupoids). Then there is a
natural functor , where is the category of -invariant maps . A version of Drinfeld's lemma states that if is a projective scheme and is the stack of quasi-coherent
sheaves of finite presentation, then is an
equivalence.
We extend this result in several directions. For proper algebraic stacks or
affine gerbes , we prove Drinfeld's lemma and deduce that
is an equivalence for very general
algebraic stacks .
For arbitrary , we show that is an equivalence when is the stack of immersions, the
stack of quasi-compact separated \'etale morphisms or any quasi-separated
Deligne-Mumford stack with separated diagonal
Coinfection by Ureaplasma spp., Photobacterium damselae and an Actinomyces-like microorganism in a bottlenose dolphin (Tursiops truncatus) with pleuropneumonia stranded along the Adriatic coast of Italy
A case of pleuropneumonia is reported in an adult male bottlenose dolphin (Tursiops truncatus) found stranded in 2014 along the Central Adriatic coast of Italy. A severe pyogranulomatous pneumonia and thoracic lymphadenopathy were present at necropsy. Numerous Splendore-Hoeppli bodies were found microscopically scattered throughout the lung. Histochemical evidence of Actinomyces-like organisms was obtained from the pulmonary parenchyma, with a strain of Photobacterium damselae subsp. piscicida and Ureaplasma spp. being also isolated from the same tissue. For the latter, a genome fragment of approximately 1400 bp from the 16s rDNA was amplified and sequenced. BLAST analysis revealed 100% identity with an uncultured Ureaplasma spp. (JQ193826.1)
Understanding Factors Associated With Psychomotor Subtypes of Delirium in Older Inpatients With Dementia
Kernel of the monodromy operator for semistable curves (Algebraic Number Theory and Related Topics 2011)
On p-adic differential equations on semistable varieties
Let V be a complete discrete valuation ring of mixed characteristic (0,p), K be the fraction field and k be the residue field. We study p-adic differential equations on a semistable variety over V.
We consider a proper semistable variety X over V and a relative normal crossing divisor D on it.
We consider on X the open U defined by the complement of the divisor D and we call U_K and U_k the generic fiber and the special fiber respectively. In an analogous way we call D_K, X_K and D_k, X_k the generic and the special fiber of D, X.
In the geometric situation described, we investigate the relations between algebraic differential equations on X_K and analytic differential equations on the rigid analytic space associated to the completion of X along its special fiber.
The main result is the existence and the full faithfulness of an algebrization functor between the following categories:
1) the category of locally free overconvergent log isocrystals on the log pair (U_k,X_k), (where the log structure is defined by the divisor given by the union of X_k e D_k), with unipotent monodromy;
2) the category of modules with connection on U_K, regular along D_K, which admit an extension to modules with connection on X_K with nilpotent residue.Sia V un anello di valutazione completo di caratteristica mista (0,p), sia K il campo delle frazioni e k il campo residuo. In questa tesi vengono studiate le equazioni differenziale p-adiche su una varieta' semistabile su V.
Consideriamo una varieta' X propria e semistabile su V e un divisore D a incroci normali relativi,
Denotiamo con U l'aperto di X definito dal complementare di D e indichiamo con U_K e U_k ripettivamente la fibra generica e la fibra speciale di U. Allo stesso modo chiamiamo X_K, D_K e X_k, D_k la fibra generica e la fibra speciale di X, D.
In questa situazione geometrica studiamo le relazioni tra le equazioni differenziali algebriche su X_K e le equazioni differenziali analitiche definite sullo spazio analitico rigido associato al completamento di X lungo la sua fibra speciale.
Il risultato principale di questa tesi e' l'esistenza e la piena fedelta' di un funtore tra le seguenti categorie:
1) la categoria dei log isocristalli localmente liberi surconvergenti definiti sulla log coppia (U_k,X_k), (dove la log e' definita dal divisore dato dall'unione di X_k e D_k), con monodromia unipotente;
2) la categoria dei moduli a connessione su U_K, regolari lungo D_K, che ammettono un' estensione a moduli a connessione su X_K con residuo nilpotente