Results 21 to 30 of about 701 (43)
Reconstruction of some cosmological models in f(R,T) gravity
, 2012 In this paper, we reconstruct cosmological models in the framework of $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the stress-energy tensor.
A. Felice De +32 more
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IFSs consisting of generalized convex contractions
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2017 In this paper we introduce the concept of iterated function system consisting of generalized convex contractions. More precisely, given n ∈ ℕ*, an iterated function system consisting of generalized convex contractions on a complete metric space (X; d) is
Georgescu Flavian
doaj +1 more source
Periodic orbits of period 3 in the disc
, 1994 Let f be an orientation preserving homeomorphism of the disc D2 which possesses a periodic point of period 3. Then either f is isotopic, relative the periodic orbit, to a homeomorphism g which is conjugate to a rotation by 2 pi /3 or 4 pi /3, or f has a ...
B Kolev +16 more
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J-class weighted shifts on the space of bounded sequences of complex numbers
, 2008 We provide a characterization of $J$-class and $J^{mix}$-class unilateral weighted shifts on $l^{\infty}(\mathbb{N})$ in terms of their weight sequences. In contrast to the previously mentioned result we show that a bilateral weighted shift on $l^{\infty}
Costakis, George, Manoussos, Antonios
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Standardization for Defence Procurement - European Handbook : CEN Workshop 10 [PDF]
, 2005 The European Commission (EC), DG Enterprise, endeavours the competitiveness of the European Defence Industry. The plethora of (national) standards, more than 10.000, are recognised by the EC as a major constraint and cost driver.
Bresson, Alain +23 more
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Metrizable universal minimal flows of Polish groups have a comeagre orbit
, 2017 We prove that, whenever $G$ is a Polish group with metrizable universal minimal flow $M(G)$, there exists a comeagre orbit in $M(G)$. It then follows that there exists an extremely amenable, closed, coprecompact $G^*$ of $G$ such that $M(G) = \hat{G/G^*}$
Melleray, Julien +2 more
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Energy conditions in f(T) gravity with higher-derivative torsion terms
, 2017 We study the energy conditions in the framework of the modi- fied gravity with higher-derivative torsional terms in the action. We discuss the viability of the model by studying the energy conditions in terms of the cosmographical parameters like Hubble,
Azizi, Tahereh, Gorjizadeh, Miysam
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Construction of minimal non-invertible skew-product maps on 2-manifolds
, 2014 Applying the Hric-J\"ager blow up technique, we give an affirmative answer to the question about the existence of non-invertible minimal circle-fibered self-maps of the Klein bottle.
Trofimchuk, Sergei, Šotola, Jakub
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Recurrent Surface Homeomorphisms
, 1998 An orientation-preserving recurrent homeomorphism of the two-sphere which is not the identity is shown to admit exactly two fixed points. A recurrent homeomorphism of a compact surface with negative Euler characteristic is periodic.Comment: 10 pages ...
Kolev, Boris, Peroueme, Marie-Christine
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Indicator sequences and indicator topologies of Fort transformation groups
, 2017 In the following text we prove that there exists a Fort transformation group with indicator sequence $(p_0,\ldots,p_n)$ if and only if $0=p_0\leq p_1\leq\cdots\leq p_n=1$, moreover we characterize all possible indicator topological spaces of Fort ...
Ebrahimifar, Fatemeh +1 more
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