Topology and smooth structure revisited

Author(s):  
Anatole Katok ◽  
Vaughn Climenhaga
Keyword(s):  
Author(s):  
Emanuele Paolini ◽  
Eugene Stepanov

The scope of the paper is twofold. We show that for a large class of measurable vector fields in the sense of Weaver (i.e. derivations over the algebra of Lipschitz functions), called in the paper laminated, the notion of integral curves may be naturally defined and characterized (when appropriate) by an ordinary differential equation. We further show that for such vector fields the notion of a flow of the given positive Borel measure similar to the classical one generated by a smooth vector field (in a space with smooth structure) may be defined in a reasonable way, so that the measure ‘flows along’ the appropriately understood integral curves of the given vector field and the classical continuity equation is satisfied in the weak sense.


2016 ◽  
Vol 24 (05) ◽  
pp. 1750061
Author(s):  
Yu ZHANG ◽  
YAN-WEI ZHAO ◽  
NAN XIANG ◽  
REN-GUO SONG

In the present study, microarc oxidation (MAO) coatings were formed on ZL101A aluminum alloy in an electrolytic bath containing 3[Formula: see text]g/L KOH [Formula: see text] 2[Formula: see text]g/L Na2WO[Formula: see text] 4[Formula: see text]g/L KF. The morphology and wearing behavior were investigated. In both electrolytes, the additives were borates (Na2B4O718[Formula: see text]g/L) and silicates (Na2SiO3 18[Formula: see text]g/L), respectively. It was found that the coating formed in borates-containing electrolyte was of compact and smooth structure than that of the one formed in silicates-containing electrolyte at the optimum treatment time. It was found that all the coatings were composed of á-Al2O3 and ã-Al2O3. The microhardness and wear tests proved that the coating formed in borates-containing electrolyte was having better mechanical properties than those of the coating formed in silicates-containing electrolyte.


2008 ◽  
Vol 190 ◽  
pp. 1-34 ◽  
Author(s):  
T. M. Gendron

The fundamental germ is a generalization of π1, first defined for laminations which arise through group actions [4]. In this paper, the fundamental germ is extended to any lamination having a dense leaf admitting a smooth structure. In addition, an amplification of the fundamental germ called the mother germ is constructed, which is, unlike the fundamental germ, a topological invariant. The fundamental germs of the antenna lamination and the PSL(2,ℤ) lamination are calculated, laminations for which the definition in [4] was not available. The mother germ is used to give a new proof of a Nielsen theorem for the algebraic universal cover of a closed surface of hyperbolic type.


2009 ◽  
Vol 147 (2) ◽  
pp. 409-417 ◽  
Author(s):  
RAREŞ RǍSDEACONU ◽  
IOANA ŞUVAINA

AbstractWe show that each of the topological 4-manifolds $\bcp^2\# k\overline{\bcp^2}$, for k = 5, 6, 7, 8 admits a smooth structure which has an Einstein metric of scalar curvature s > 0, a smooth structure which carries an Einstein metric with s < 0 and infinitely many non-diffeomorphic smooth structures which do not admit Einstein metrics. We also exhibit new examples of higher dimensional manifolds carrying Einstein metrics of both positive and negative scalar curvature.


2013 ◽  
Vol 773-774 ◽  
pp. 616-625 ◽  
Author(s):  
Bing Jing Lin ◽  
Hong Tao Zhu ◽  
A. Kiet Tieu ◽  
Gerry Triani

An ultra- thin Ti film with a thickness of less than 30 nm was deposited on the surface of a silicon wafer by the filtered arc deposition system. A novel technique was adopted to create a height step between the coated area and non-coated area (silicon wafer) during deposition. The surface morphology and thickness of the film was detected by atomic force microscopy (AFM). The AFM results showed that the deposited film formed a smooth structure on the silicon wafer and the height step between the coating and silicon wafer was clear enough to give the thickness of the deposited film. The composition of the deposited film was detected by a combined use of Ellipsometry and AFM. Natural oxidisation of Ti (TiO2) was found on the top of the Ti film after deposition, and the thickness of TiO2 was determined by ellipsometry to be about 0.6 nm.


2014 ◽  
Vol 164 ◽  
pp. 242-247
Author(s):  
James Cruickshank ◽  
Jonathan McLaughlin

2014 ◽  
Vol 18 (sup2) ◽  
pp. S2-387-S2-392
Author(s):  
Y. H. Ma ◽  
Y. C. Liu ◽  
J. Peng ◽  
S. S. Ma ◽  
L. Guo ◽  
...  

1988 ◽  
Vol 43 (1) ◽  
pp. 14-16 ◽  
Author(s):  
J. Peinke ◽  
J. Parisi ◽  
B. Röhricht ◽  
O. E. Rössler ◽  
W. Metzler

Abstract Generalized Mandelbrot sets arise in perturbed (non-analytic) versions of the complex logistic map. Numerically, it contains smooth portions as shown previously. To exclude that this result is specific to particular initial conditions only, the structure of the analogue to the Fatou set is looked at in the region in question. The set of non-divergent points is being "eaten up" by a smooth invading boundary. Therefore, the same type of decomposition applies independent of position in parameter space, in the region in question.


2017 ◽  
Vol 164 (2) ◽  
pp. 369-380
Author(s):  
CHRISTIAN LANGE

AbstractWe prove that every piecewise linear manifold of dimension up to four on which a finite group acts by piecewise linear homeomorphisms admits a compatible smooth structure with respect to which the group acts smoothly.


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