• Honam Mathematical Journal
• /
• v.20 no.1
• /
• pp.121-133
• /
• 1998

We find some properties of the pro-torsion products. Under the suitable conditions, we also show that the map ${\bar{H}}_P({\chi};G){\rightarrow}{\bar{H}}_p^{s(r)}({\chi};G)$ is an isomorphism and the n-th homotopy group of X is isomorphic to the n-th ${\check{C}}ECH$ homology group.

• Journal of applied mathematics & informatics
• /
• v.23 no.1_2
• /
• pp.537-545
• /
• 2007

We investigate complemented Banach sublattices of the Banach envelope of $Weak_L1$. In particular, the Banach envelope of $Weak_L1$ contains a complemented Banach sublattice that is isometrically isomorphic to a nonseparable Banach lattice $l_p(S),\;1{\leq}p<{\infty}\;and\;|S|{\leq}2^{{\aleph}0}$.

• The Pure and Applied Mathematics
• /
• v.16 no.3
• /
• pp.283-296
• /
• 2009

Let f(x) = $x^n\;+\;a$ be a binomial polynomial in Z[x] and $f_m(x)$ be the m-th iterate of f(x). In this work we study a necessary condition to be the Galois group of $f_m(x)$ is isomorphic to a wreath product group $[C_n]^m$ where $C_n$ is a cyclic group of order n.

• Bulletin of the Korean Mathematical Society
• /
• v.36 no.2
• /
• pp.259-272
• /
• 1999

In [6], Godefroy defined octahedral norms to give an isomorphic characterization of spaces containing $\ell_1$. Here we will show that such norms can be defined by using "average distances" as introduced in[1]. Also, we indicate some other properties of average distances : in particular, we give some estimates for their values in the product of two spaces, furnished with the max or the sum norm.

• Journal of the Chungcheong Mathematical Society
• /
• v.32 no.1
• /
• pp.87-95
• /
• 2019

The homothety classes of lattices in a two dimensional vector space over a nonarchimedean local field form a regular tree ${\mathcal{T}}$ of degree q + 1 on which the projective linear group acts naturally where q is the order of the residue field. We show that for any finite regular combinatorial graph of even degree q + 1, there exists a torsion free discrete subgroup ${\Gamma}$ of the projective linear group such that ${\mathcal{T}}/{\Gamma}$ is isomorphic to the graph.

• Korean Journal of Mathematics
• /
• v.27 no.3
• /
• pp.595-612
• /
• 2019

In this paper, we introduce the concept of ${\beta}$-fuzzy filters in MS-algebras and ${\beta}$-fuzzy filters are characterized in terms of boosters. It is proved that the lattice of ${\beta}$-fuzzy filters is isomorphic to the fuzzy ideal lattice of boosters.

• Honam Mathematical Journal
• /
• v.41 no.3
• /
• pp.631-650
• /
• 2019

In this paper, for discrete groups G and K, we show that the bounded cohomology group of $G{\times}K$ is isomorphic to the cohomology group of the complex of the projective tensor product $B^*(G){\hat{\otimes}}B^*(K)$, where $B^*(G)$ and $B^*(G)$ are the complexes of bounded cochains with real coefficients ${\mathbb{R}}$ of G and K, respectively.

• Bulletin of the Korean Mathematical Society
• /
• v.56 no.1
• /
• pp.229-243
• /
• 2019

We use the so-called pseudoinversion of degenerate metrics technique on foliated compact null hypersurface, $M^{n+1}$, in Lorentzian manifold ${\overline{M}}^{n+2}$, to derive an integral formula involving the r-th order mean curvatures of its foliations, ${\mathcal{F}}^n$. We apply our formula to minimal foliations, showing that, under certain geometric conditions, they are isomorphic to n-dimensional spheres. We also use the formula to deduce expressions for total mean curvatures of such foliations.

• Honam Mathematical Journal
• /
• v.41 no.2
• /
• pp.321-328
• /
• 2019

We completely characterize the isomorphic class of those associative unitary rings whose elements are sums of four commuting idempotents. Our main theorem enlarges results due to Hirano-Tominaga (Bull. Austral. Math. Soc., 1988), Tang et al. (Lin. & Multilin. Algebra, 2019), Ying et al. (Can. Math. Bull., 2016) as well as results due to the author in (Alban. J. Math., 2018), (Gulf J. Math., 2018), (Bull. Iran. Math. Soc., 2018) and (Boll. Un. Mat. Ital., 2019).

• The Pure and Applied Mathematics
• /
• v.30 no.1
• /
• pp.15-24
• /
• 2023

In this paper, we show that bounded Hochschild homology and cohomology of associated matrix Banach algebra 𝔊(𝔄, R, S, 𝔅) to a Morita context 𝔐(𝔄, R, S, 𝔅, { }, [ ]) are isomorphic to those of the Banach algebra 𝔄. Consequently, we indicate that the n-amenability and simplicial triviality of 𝔊(𝔄, R, S, 𝔅) are equivalent to the n-amenability and simplicial triviality of 𝔄.