ZrTe5 and HfTe5 have attracted increasingly attention recently since the theoretical prediction of being topological insulators (TIs). However, subsequent works show many contradictions about their topolog-ical nature. Three possible phases, i.e. strong TI, weak TI, and Dirac semi-metal, have been observed in different experiments until now. Essentially whether ZrTe5 or HfTe5 has a band gap or ...

We present an elementary proof of the well known theorem that the limit of a levelwise weak equivalence of towers of fibrations of topological spaces is a weak equivalence, without mentioning lim.

We show that the n center problem in R 3 has positive topological entropy for n 3. The proof is based on global regularization of sin-gularities and the results of Gromov and Paternain on the topological entropy of geodesic ows. The n-center problem in S 3 is also studied.

In this paper we first introduce a new multiplication on triangular Banach algebras. Then we study their Arens regularity as well as their topological centers . In this paper we first introduce a new multiplication on triangular Banach algebras. Then we study their Arens regularity as well as their topological centers . In this paper we first introduce a new multiplication on triangular Banach ...

These notes give a summary of results that everyone who does work in functional analysis should know about the weak topology on locally convex topological vector spaces and the weak-* topology on their dual spaces. The most striking of the results we prove is Theorem 9, which shows that a subset of a locally convex space is bounded if and only if it is weakly bounded. It is straightforward to p...

We study the topological centers of $nth$ dual of Banach $mathcal{A}$-modules and we extend some propositions from Lau and "{U}lger into $n-th$ dual of Banach $mathcal{A}-modules$ where $ngeq 0$ is even number. Let   $mathcal{B}$   be a Banach  $mathcal{A}-bimodule$. By using some new conditions, we show that $ Z^ell_{mathcal{A}^{(n)}}(mathcal{B}^{(n)})=mathcal{B}^{(n)}$ and $ Z^ell_{mathcal{B}...

We study an inhomogeneous critical Ising chain in a transverse field whose couplings decay exponentially from the center. In strong inhomogeneity limit, we apply Fisher's renormalization group to show that ground state is formed by concentric singlets similar those of rainbow XX model. weak map model massless Majorana fermion living hyperbolic space-time, where, using conformal theory technique...

In this paper, we will provide some examples of Banach spaces that are Gâteaux differentiability spaces but not weak Asplund, weak Asplund but not in class(
̃), in class(
̃) but whose dual space is not weak∗ fragmentable. We begin with some definitions. A Banach space X is called a weak Asplund space [almost weak Asplund] (Gâteaux differentiability space) if each continuous convex function define...

Topological defects are produced during phase transitions in the very early Universe. They arise in most unified theories of strong, weak and electromagnetic interactions. These lectures focus on the role of topological defects in cosmology, with particular emphasis on the models of structure formation based on defects. The role of topological defects in baryogenesis is also reviewed. ⋆ Based o...