scholarly journals No topological condition implies equality of polynomial and rational hulls

2019 ◽  
Vol 147 (12) ◽  
pp. 5195-5207
Author(s):  
Alexander J. Izzo
2008 ◽  
Vol 51 (2) ◽  
pp. 229-235
Author(s):  
Mary Hanley

AbstractLet Ω be a domain in ℝn (n ≥ 2). We find a necessary and sufficient topological condition on Ω such that, for anymeasure μ on ℝn, there is a function u with specified boundary conditions that satisfies the Poisson equation Δu = μ on Δ in the sense of distributions.


Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 304 ◽  
Author(s):  
Kyriakos Papadopoulos ◽  
Nazli Kurt ◽  
Basil Papadopoulos

We give a topological condition for a generic sliced space to be globally hyperbolic without any hypothesis on lapse function, shift function, and spatial metric.


2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Aybike Çatal-Özer ◽  
Emine Diriöz

Abstract In a supersymmetric compactification of Type II supergravity, preservation of $$ \mathcal{N} $$ N = 1 supersymmetry in four dimensions requires that the structure group of the generalized tangent bundle TM ⨁ T∗M of the six dimensional internal manifold M is reduced from SO(6) to SU(3) × SU(3). This topological condition on the internal manifold implies existence of two globally defined compatible pure spinors Φ1 and Φ2 of non-vanishing norm. Furthermore, these pure spinors should satisfy certain first order differential equations. In this paper, we show that non-Abelian T-duality (NATD) is a solution generating transformation for these pure spinor equations. We first show that the pure spinor equations are covariant under Pin(d, d) transformations. Then, we use the fact NATD is generated by a coordinate dependent Pin(d, d) transformation. The key point is that the flux produced by this transformation is the same as the geometric flux associated with the isometry group, with respect to which one implements NATD. We demonstrate our method by studying NATD of certain solutions of Type IIB supergravity with SU(2) isometry and SU(3) structure.


Author(s):  
Kyriakos Papadopoulos ◽  
Nazli Kurt ◽  
Basil K. Papadopoulos

We give a topological condition for a generic sliced space to be globally hyperbolic, without any hypothesis on the lapse function, shift function and spatial metric.


2019 ◽  
Vol 30 (08) ◽  
pp. 1950046
Author(s):  
Alexandre Ramos-Peon ◽  
Riccardo Ugolini

Given a Stein manifold with the density property, we show that under a suitable topological condition it is possible to prescribe derivatives at a finite number of points to automorphisms depending holomorphically on a Stein parameter. This is an Oka property of the manifold and is related to its holomorphic flexibility.


1980 ◽  
Vol 32 (3) ◽  
pp. 657-685 ◽  
Author(s):  
F. Dashiell ◽  
A. Hager ◽  
M. Henriksen

This paper studies sequential order convergence and the associated completion in vector lattices of continuous functions. Such a completion for lattices C(X) is related to certain topological properties of the space X and to ring properties of C(X). The appropriate topological condition on the space X equivalent to this type of completeness for the lattice C(X) was first identified, for compact spaces X, in [6]. This condition is that every dense cozero set S in X should be C*-embedded in X (that is, all bounded continuous functions on S extend to X). We call Tychonoff spaces X with this property quasi-F spaces (since they generalize the F-spaces of [12]).In Section 1, the notion of a completion with respect to sequential order convergence is first described in the setting of a commutative lattice group G.


2004 ◽  
Vol 15 (06) ◽  
pp. 573-580 ◽  
Author(s):  
MITSUHIRO ITOH

We show in this paper by applying the Seiberg–Witten theory developed by Taubes and LeBrun that a compact almost Kähler–Einstein 4-manifold of negative scalar curvature s is Kähler–Einstein if and only if the L2-norm satisfies ∫Ms2dv=32π2(2χ+3τ)(M). The Einstein condition can be weakened by the topological condition (2χ+3τ)(M)>0.


2013 ◽  
Vol 11 (10) ◽  
Author(s):  
Dimcho Stankov ◽  
Tzonio Tzonev

AbstractIn this paper we consider several conditions for sequences of points in M(H ∞) and establish relations between them. We show that every interpolating sequence for QA of nontrivial points in the corona $$M(H^\infty )\backslash \mathbb{D}$$ of H ∞ is a thin sequence for H ∞, which satisfies an additional topological condition. The discrete sequences in the Shilov boundary of H ∞ necessarily satisfy the same condition.


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