Search results for " Operator"
showing 10 items of 931 documents
Nonlinear Nonhomogeneous Elliptic Problems
2019
We consider nonlinear elliptic equations driven by a nonhomogeneous differential operator plus an indefinite potential. The boundary condition is either Dirichlet or Robin (including as a special case the Neumann problem). First we present the corresponding regularity theory (up to the boundary). Then we develop the nonlinear maximum principle and present some important nonlinear strong comparison principles. Subsequently we see how these results together with variational methods, truncation and perturbation techniques, and Morse theory (critical groups) can be used to analyze different classes of elliptic equations. Special attention is given to (p, 2)-equations (these are equations driven…
Maximal Operators with Respect to the Numerical Range
2018
Let $\mathfrak{n}$ be a nonempty, proper, convex subset of $\mathbb{C}$. The $\mathfrak{n}$-maximal operators are defined as the operators having numerical ranges in $\mathfrak{n}$ and are maximal with this property. Typical examples of these are the maximal symmetric (or accretive or dissipative) operators, the associated to some sesquilinear forms (for instance, to closed sectorial forms), and the generators of some strongly continuous semi-groups of bounded operators. In this paper the $\mathfrak{n}$-maximal operators are studied and some characterizations of these in terms of the resolvent set are given.
Annihilation Operators for Exponential Spaces in Subdivision
2022
We investigate properties of differential and difference operators annihilating certain finite-dimensional subspaces of exponential functions in two variables that are connected to the representation of real-valued trigonometric and hyperbolic functions. Although exponential functions appear in a variety of contexts, the motivation behind this work comes from considering subdivision schemes with the capability of preserving those exponential functions required for an exact description of surfaces parametrized in terms of trigonometric and hyperbolic functions.
La supervisione: strumento di formazione continua per operatori di Comunità Terapeutiche Assistite.
2012
lavoro nelle organizzazioni sociali si presenta oggi complesso e oltremodo denso di criticità. La trasformazione dei quadri di riferimento normativi, la complessità socio-politica e le difficoltà legate agli specifici interventi incidono profondamente sui gruppi di lavoro che o-perano nel sociale, incrementando la già diffusa necessità di essere supportati. Il seguente lavo-ro, a tal fine, terrà fortemente in considerazione la ricchezza e la pluralità dei bisogni che gli operatori del sociale (cooperative, comunità, ecc.) esprimono, rimandando ad un’idea di “cura del loro sviluppo e della loro funzione” complessa e variegata (Basaglia, 1968). È in questa pro-spettiva che lo strumento della …
Monotony Based Imaging in EIT
2010
We consider the problem of determining conductivity anomalies inside a body from voltage‐current measurements on its surface. By combining the monotonicity method of Tamburrino and Rubinacci with the concept of localized potentials, we derive a new imaging method that is capable of reconstructing the exact (outer) shape of the anomalies. We furthermore show that the method can be implemented without solving any non‐homogeneous forward problems and show a first numerical result.
Par svārstīgiem nestriktiem Hamahera agregācijas operatoriem daudzkritēriju lēmumu pieņemšanai
2015
Bakalaura darbs veltīts dažiem svārstīgo nestrikto Hamahera agregācijas operatoru pielietojumiem daudzkritēriju lēmumu pieņemšanas procesa modelēšanā. Darbā aplūkoti tādi nestriktās matemātikas jēdzieni, kā t-norma, t-konorma, involūcija, svārstīga nestrikta kopa, darbības ar svārstīgiem nestriktiem elementiem, kas nepieciešami, lai definētu svārstīgo nestrikto agregācijas operatoru. Izmantojot svārstīgos nestriktos Hamahera agregācijas operatorus, aprakstīts daudzkritēriju lēmumu pieņemšanas modelis, kas pielietots skaitlisku datu apstrādē. Iegūtie rezultāti analizēti.
A best proximity point approach to existence of solutions for a system of ordinary differential equations
2019
We establish the existence of a solution for the following system of differential equations (y x ′′((t t ) ) = = g f ((t t ,y x ((t t )) )) ,y x ((t t 0 0) ) = = x x *** in the space of all bounded and continuous real functions on [0, +∞[. We use best proximity point methods and measure of noncompactness theory under suitable assumptions on f and g. Some new best proximity point theorems play a key role in the above result.
Systems of quasilinear elliptic equations with dependence on the gradient via subsolution-supersolution method
2017
For the homogeneous Dirichlet problem involving a system of equations driven by \begin{document}$(p,q)$\end{document} -Laplacian operators and general gradient dependence we prove the existence of solutions in the ordered rectangle determined by a subsolution-supersolution. This extends the preceding results based on the method of subsolution-supersolution for systems of elliptic equations. Positive and negative solutions are obtained.
Abelian varieties and theta functions associated to compact Riemannian manifolds; constructions inspired by superstring theory
2012
We look into a construction of principal abelian varieties attached to certain spin manifolds, due to Witten and Moore-Witten around 2000 and try to place it in a broader framework. This is related to Weil intermediate Jacobians but it also suggests to associate abelian varieties to polarized even weight Hodge structures. The latter construction can also be explained in terms of algebraic groups which might be useful from the point of view of Tannakian categories. The constructions depend on moduli much as in Teichm\"uller theory although the period maps in general are only real analytic. One of the nice features is how the index for certain differential operators canonically associated to …
Estimates for Sums of Eigenvalues of the Free Plate via the Fourier Transform
2017
Using the Fourier transform, we obtain upper bounds for sums of eigenvalues of the free plate.