scholarly journals SIMULTANEOUS EXTENSION OPERATORS FOR THE DENSITY TOPOLOGY

1999 ◽  
Vol 25 (1) ◽  
pp. 223
Author(s):  
Kolář
2010 ◽  
Vol 53 (4) ◽  
pp. 719-729
Author(s):  
I. Stasyuk ◽  
E. D. Tymchatyn

AbstractWe consider the problem of simultaneous extension of continuous convex metrics defined on subcontinua of a Peano continuum. We prove that there is an extension operator for convex metrics that is continuous with respect to the uniform topology.


2014 ◽  
Vol 57 (1) ◽  
pp. 178-187 ◽  
Author(s):  
Patrick J. Rabier

AbstractWe prove that if f : ℝN → ℝ̄ is quasiconvex and U ⊂ ℝN is open in the density topology, then supU ƒ = ess supU f ; while infU ƒ = ess supU ƒ if and only if the equality holds when U = RN: The first (second) property is typical of lsc (usc) functions, and, even when U is an ordinary open subset, there seems to be no record that they both hold for all quasiconvex functions.This property ensures that the pointwise extrema of f on any nonempty density open subset can be arbitrarily closely approximated by values of ƒ achieved on “large” subsets, which may be of relevance in a variety of situations. To support this claim, we use it to characterize the common points of continuity, or approximate continuity, of two quasiconvex functions that coincide away from a set of measure zero.


1978 ◽  
Vol 75 (2) ◽  
pp. 579-588 ◽  
Author(s):  
Franklin Tall
Keyword(s):  

2003 ◽  
Vol 4 (2) ◽  
pp. 509 ◽  
Author(s):  
Wladyslaw Wilczynski

<p>We shall show that the space of all approximately continuous functions with the topology of pointwise convergence is not homeomorphic to its category analogue.</p>


2015 ◽  
Vol 62 (1) ◽  
pp. 67-87
Author(s):  
Wojciech Wojdowski

Abstract We present a generalization of the Tc -density topology introduced in [WO5] as a topology involving both category and measure approach to the notion of density. We construct an ascending sequence of density topologies which leads to -density topology including all previous topologies. We examine several basic properties of the topologies.


2011 ◽  
Vol 201-203 ◽  
pp. 1308-1311 ◽  
Author(s):  
Fa Rong Du ◽  
Zhi Tao

The topology optimization and analysis were studied on the area of piston pin boss for a high-speed gasoline engine based on the variable density topology optimization method. Firstly, the model of the variable density topology optimization was founded. Then, the topology optimization and topology deconstruction on the piston pin boss were carried out by using Hyper Works. In this process, the minimum mass of piston was pursued as an objective function and the displacements of specified nodes on the piston skirt were made as constraints. Based on the topology optimization, the piston configuration of curved rod frame was designed. The complex stress of the piston before and after optimization was calculated respectively by ANSYS. The calculation results indicate that the piston mass can be lightened by 30% through optimizing under the same level of maximal stress, with satisfying the strength requirements. Therefore, the aim of piston lightweight is achieved, and there is no stress concentration in the area of the optimizing piston pin boss, which is propitious to the deformation compatibility of the piston pin boss.


1989 ◽  
Vol 22 (3) ◽  
Author(s):  
Wojciech Wojdowski
Keyword(s):  

2015 ◽  
Vol 58 (3) ◽  
pp. 637-647 ◽  
Author(s):  
SILVANO DELLADIO

AbstractSome well-known results about the 2-density topology on ${\mathcal R}$ (in particular in the context of the Lusin–Menchoff property) are extended to τbm, i.e. the m-density topology on ${\mathcal R}$n with m ∈ (n,+∞). Every set of finite perimeter in ${\mathcal R}$n is equivalent (in measure) to a set in τbm0, where m0=n+1+${1\over n-1}$. There exists a set of finite perimeter in ${\mathcal R}$n which is not equivalent (in measure) to any member in the a.e.-modification of τbm, whatever m ∈ [n,+∞).


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