scholarly journals Extension of Positive Currents with Special Properties of Monge-Ampère Operators

2013 ◽  
Vol 113 (1) ◽  
pp. 108 ◽  
Author(s):  
Ahmad L. al Abdulaali

In this paper we study the extension of currents across small obstacles. Our main results are: 1) Let $A$ be a closed complete pluripolar subset of an open subset $\Omega$ of $\mathsf{C}^n$ and $T$ be a negative current of bidimension $(p,p)$ on $\Omega\setminus A$ such that $dd^{c}T\geq-S$ on $\Omega\setminus A$ for some positive plurisubharmonic current $S$ on $\Omega$. Assume that the Hausdorff measure $\mathscr{H}_{2p}(A\cap \overline{\operatorname{Supp} T})=0$. Then $\widetilde{T}$ exists. Furthermore, the current $R= \widetilde{dd^{c}T}-{dd}^{c} \widetilde{T}$ is negative supported in $A$. 2) Let $u$ be a positive strictly $k$-convex function on an open subset $\Omega$ of $\mathsf{C}^n$ and set $A=\{z\in\Omega:u(z)=0\}$. Let $T$ be a negative current of bidimension $(p,p)$ on $\Omega\setminus A$ such that $dd^{c}T\geq -S$ on $\Omega\setminus A$ for some positive plurisubharmonic (or $dd^{c}$-negative) current $S$ on $\Omega$. If $p\geq k+1$, then $\widetilde{T}$ exists. If $p\geq k+2$, $dd^{c}S\leq 0$ and $u$ of class $\mathscr{C}^{2}$, then $\widetilde{dd^{c}T}$ exists and $\widetilde{dd^{c}T}= dd^{c}\widetilde{T}$.

2020 ◽  
Vol 18 (1) ◽  
pp. 1-9
Author(s):  
Carlo Mariconda ◽  
Giulia Treu

Abstract We consider the classical functional of the Calculus of Variations of the form $$\begin{array}{} \displaystyle I(u)=\int\limits_{{\it\Omega}}F(x, u(x), \nabla u(x))\,dx, \end{array}$$ where Ω is a bounded open subset of ℝn and F : Ω × ℝ × ℝn → ℝ is a Carathéodory convex function; the admissible functions u coincide with a prescribed Lipschitz function ϕ on ∂Ω. We formulate some conditions under which a given function in ϕ + $\begin{array}{} \displaystyle W^{1,p}_0 \end{array}$(Ω) with I(u) < +∞ can be approximated in the W1,p norm and in energy by a sequence of smooth functions that coincide with ϕ on ∂Ω. As a particular case we obtain that the Lavrentiev phenomenon does not occur when F(x, u, ξ) = f(x, u) + h(x, ξ) is convex and x ↦ F(x, 0, 0) is sufficiently smooth.


Filomat ◽  
2017 ◽  
Vol 31 (18) ◽  
pp. 5827-5831
Author(s):  
Reza Mirzaie

We find an upper bound for the Hausdorff dimension of the nondifferentiability set of a continuous convex function defined on a Riemannian manifold. As an application, we show that the boundary of a convex open subset of Rn, n ? 2, has Hausdorff dimension at most n - 2.


Author(s):  
Ehud Hrushovski ◽  
François Loeser

This chapter includes some additional material on homotopies. In particular, for a smooth variety V, there exists an “inflation” homotopy, taking a simple point to the generic type of a small neighborhood of that point. This homotopy has an image that is properly a subset of unit vector V, and cannot be understood directly in terms of definable subsets of V. The image of this homotopy retraction has the merit of being contained in unit vector U for any dense Zariski open subset U of V. The chapter also proves the continuity of functions and homotopies using continuity criteria and constructs inflation homotopies before proving GAGA type results for connectedness. Additional results regarding the Zariski topology are given.


1986 ◽  
Vol 12 (1) ◽  
pp. 118
Author(s):  
Meinershagen
Keyword(s):  

1987 ◽  
Vol 13 (1) ◽  
pp. 223
Author(s):  
Meinershagen
Keyword(s):  

1983 ◽  
Vol 20 (04) ◽  
pp. 835-842
Author(s):  
David Assaf

The paper presents sufficient conditions for certain functions to be convex. Functions of this type often appear in Markov decision processes, where their maximum is the solution of the problem. Since a convex function takes its maximum at an extreme point, the conditions may greatly simplify a problem. In some cases a full solution may be obtained after the reduction is made. Some illustrative examples are discussed.


1961 ◽  
Vol 201 (5) ◽  
pp. 873-880 ◽  
Author(s):  
T. Hoshiko ◽  
Nick Sperelakis

In frog ventricular strips bathed in Ca-free Ringer's solution containing 6–30 mm/liter Mg and treated with conditioning current pulses, propagation became impaired. An exaggerated foot, or prepotential, was consistently more prominent when the conditioned strip was stimulated from one end than from the other. Occasionally a prepotential in isolation alternated with a prepotential plus action potential response. After further treatment with current pulses, propagation failed in the direction of negative current flow. Thresholds of impaled cells were identical. Bidirectional propagation was restored in Ringer's solution. Conditioning pulses of reversed polarity induced unidirectional propagation in the reverse direction. Propagation in frog sartorius muscle was not blocked under similar conditions. Prepotentials and unidirectional propagation may be explained by junctional transmission from cell to cell.


Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 966
Author(s):  
Anna Dobosz ◽  
Piotr Jastrzębski ◽  
Adam Lecko

In this paper we study a certain differential subordination related to the harmonic mean and its symmetry properties, in the case where a dominant is a linear function. In addition to the known general results for the differential subordinations of the harmonic mean in which the dominant was any convex function, one can study such differential subordinations for the selected convex function. In this case, a reasonable and difficult issue is to look for the best dominant or one that is close to it. This paper is devoted to this issue, in which the dominant is a linear function, and the differential subordination of the harmonic mean is a generalization of the Briot–Bouquet differential subordination.


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