1,227 research outputs found
Riesz transforms on groups
Full text linkWe prove the -boundedness for all of the first-order
Riesz transforms associated with the Laplacian
on the -group ; here and are left-invariant vector
fields on in the directions of the factors and
respectively. This settles a question left open in previous work of Hebisch and
Steger (who proved the result for ) and of Gaudry and Sj\"ogren (who
only considered ). The main novelty here is that we can treat the case
and include the Riesz transform in the direction of
; an operator-valued Fourier multiplier theorem on
turns out to be key to this purpose. We also establish a weak type
endpoint for the adjoint Riesz transforms in the direction of .
By transference, our results imply the -boundedness for
of the first-order Riesz transforms associated with the Schr\"odinger operator
on the real line.Comment: 40 page
La tutela processuale europea dell'ambiente. Problemi di legittimazione delle associazioni ambientaliste
No full textIl contributo nasce dalla relazione tenuta dalla Professoressa Giovanna Ligugnana, esperta della tematica relativa ai problemi di legittimazione delle associazioni ambientaliste in ambito europeo, presso il Dipartimento di Scienze Politiche dell'Università La Sapienza di Roma. Nell'articolo si offre una ricostruzione dell'evoluzione normativa e giurisprudenziale di matrice europea sviluppatasi attorno al diritto di accesso alla giustizia ambientale, in particolare delle associazioni ambientaliste, ripercorrendone i tratti e le questioni più significative, dalla Convenzione di Aarhus fino agli scenari più recenti
Amministrazione in transizione. Riflessioni sulla transizione ecologica e sull’organizzazione amministrativa al suo servizio
Full text linkIl contributo si sofferma sul riassetto del Ministero dell’Ambiente, che ha portato all’istituzione del Ministero della Transizione Ecologica. Alla luce del ruolo di primo piano assunto nel recente dibattito scientifico, in prima istanza si cerca di inquadrare il concetto di transizione ecologica in una prospettiva storica. In seconda istanza, attraverso gli esempi dell’ordinamento francese e spagnolo, viene data contezza di come la transizione ecologica sia stata utilizzata per il rinnovamento dei modelli ministeriali precedentemente posti a presidio dell’ambiente. Da ultimo, nell’analizzare la nuova struttura ministeriale italiana, vengono svolte delle riflessioni sul potenziale rapporto tra organizzazione amministrativa, funzioni e obiettivi normativi da perseguire, al fine di verificare se la transizione del modello amministrativo di riferimento sia all’altezza delle sfide della transizione ecologica
Sulla rilevanza giuridica delle attività funebri tra vecchie esigenze e nuove prospettive
No full textThe article aims to systematise funeral activities in the Italian framework by highlighting their main legally relevant features and verifying whether they can be qualified as public service or local public service activities. To this end, the analysis moves from the main doctrinal approaches of this topic and takes into account the regulatory trends, both the existing legislation and the law being established
La neutralità tecnologica: un nuovo principio del diritto dell'ambiente?
No full textIl diritto positivo è sempre più pervaso dal concetto di neutralità tecnologica, anche
con riferimento alla normativa in materia di transizione ecologica e tutela dell’ambiente.
Si tratta di un principio giuridico? Afferisce al diritto dell’ambiente? Il
legislatore e le amministrazioni sono tenuti al suo rispetto nella produzione e
attuazione di regole giuridiche? Sebbene l’esame della normativa vigente sembri
prospettarne la qualificazione come principio giuridico espresso settoriale, ma
difficilmente applicabile nell’attuazione delle politiche ambientali, nel contributo
saranno esposti taluni elementi che renderebbero adattabile lo stesso anche nella
materia ambientale.Positive law is increasingly influenced by the concept of technological neutrality,
including in relation to regulations on ecological transition and environmental protection.
Is this a principle of law? Does it pertain to environmental law? Are legislators
and administrations required to comply with it in the creation and implementation of
legal rules? While an analysis of the current legislation suggests its classification as an
expressed sectoral legal principle, albeit one that is difficult to apply in the implementation
of environmental policies, this contribution will present certain elements that
could make it adaptable to the environmental field as well
La tutela processuale europea dell'ambiente. Problemi di legittimazione delle associazioni ambientaliste
No full textIl contributo nasce dalla relazione tenuta dalla Professoressa Giovanna Ligugnana, esperta della tematica relativa ai problemi di legittimazione delle associazioni ambientaliste in ambito europeo, presso il Dipartimento di Scienze Politiche dell'Università La Sapienza di Roma. Nell'articolo si offre una ricostruzione dell'evoluzione normativa e giurisprudenziale di matrice europea sviluppatasi attorno al diritto di accesso alla giustizia ambientale, in particolare delle associazioni ambientaliste, ripercorrendone i tratti e le questioni più significative, dalla Convenzione di Aarhus fino agli scenari più recenti
Sull’inadempimento degli obblighi della direttiva 2008/50/CE «qualità dell’aria ambiente» e l’applicazione di misure detentive coercitive. Il caso Deutsche Umwelthilfe eV (C-752/18)
No full textThe Court of Justice of the European Union pronounces on the nonfulfilment of the obligations of Directive 2008/50/EC on ambient air quality and cleaner air for Europe by a Member State. The Court was asked to clarify if the European Union law allowed national judge to order the coercive detention of office holders responsible of the violation of the EU Directive. The importance and the innovation of the judgement in question lies in the fact that the preliminary ruling concerns the relation between the effectiveness of the European Union law and the respect of the fundamental rights, in this case the right to liberty and the right to an effective remedy
Sulla rilevanza giuridica delle attività funebri tra vecchie esigenze e nuove prospettive
No full textThe article aims to systematise funeral activities in the Italian framework by highlighting their main legally relevant features and verifying whether they can be qualified as public service or local public service activities. To this end, the analysis moves from the main doctrinal approaches of this topic and takes into account the regulatory trends, both the existing legislation and the law being established
Algebras of differential operators on Lie groups and spectral multipliers
Full text linkLet (X, μ) be a measure space, and let L1, . . . ,Ln be (possibly unbounded) selfadjoint
operators on L2(X, μ), which commute strongly pairwise, i.e., which
admit a joint spectral resolution E on Rn. A joint functional calculus is then
defined via spectral integration: for every Borel function m : Rn → C,
m(L) = m(L1, . . . ,Ln) =
∫ Rn m(λ) dE(λ) is a normal operator on L2(X, μ), which is bounded if and only if m - called
the joint spectral multiplier associated to m(L) - is (E-essentially) bounded.
However, the abstract theory of spectral integrals does not tackle the following
problem: to find conditions on the multiplier m ensuring the boundedness of
m(L) on Lp(X, μ) for some p ≠ 2.
We are interested in this problem when the measure space is a connected Lie
group G with a right Haar measure, and L1, . . . ,Ln are left-invariant differential
operators on G. In fact, the question has been studied quite extensively in the
case of a single operator, namely, a sublaplacian or a higher-order analogue.
On the other hand, for multiple operators, only specific classes of groups and
specific choices of operators have been considered in the literature.
Suppose that L1, . . . ,Ln are formally self-adjoint, left-invariant differential
operators on a connected Lie group G, which commute pairwise (as operators
on smooth functions). Under the assumption that the algebra generated by
L1, . . . ,Ln contains a weighted subcoercive operator --- a notion due to [ER98],
including positive elliptic operators, sublaplacians and Rockland operators---we
prove that L1, . . . ,Ln are (essentially) self-adjoint and strongly commuting on
L2(G). Moreover, we perform an abstract study of such a system of operators,
in connection with the algebraic structure and the representation theory of G,
similarly as what is done in the literature for the algebras of differential operators
associated with Gelfand pairs.
Under the additional assumption that G has polynomial volume growth,
weighted L1 estimates are obtained for the convolution kernel of the operator
m(L) corresponding to a compactly supported multiplier m satisfying some
smoothness condition. The order of smoothness which we require on m is related
to the degree of polynomial growth of G. Some techniques are presented,
which allow, for some specific groups and operators, to lower the smoothness
requirement on the multiplier.
In the case G is a homogeneous Lie group and L1, . . . ,Ln are homogeneous
operators, a multiplier theorem of Mihlin-H\"ormander type is proved, extending
the result for a single operator of [Chr91] and [MM90]. Further, a product theory
is developed, by considering several homogeneous groups Gj , each of which with
its own system of operators; a non-conventional use of transference techniques
then yields a multiplier theorem of Marcinkiewicz type, not only on the direct
product of the Gj , but also on other (possibly non-homogeneous) groups, containing
homomorphic images of the Gj . Consequently, for certain non-nilpotent
groups of polynomial growth and for some distinguished sublaplacians, we are
able to improve the general result of [Ale94]
- …
