• 대한수학회보
• /
• 제55권2호
• /
• pp.507-514
• /
• 2018

Let $\{{\varphi}_n\}_{n{\geq}1}$ be a sequence of analytic self-maps of ${\mathbb{D}}$. It is proved that if the union set of the ranges of the composition operators $C_{{\varphi}_n}$ on the weighted Bergman spaces contains the disk algebra, then ${\varphi}_k$ is an automorphism of ${\mathbb{D}}$ for some $k{\geq}1$.

• 호남수학학술지
• /
• 제36권4호
• /
• pp.739-753
• /
• 2014

In this study, it is aimed to analyze how relationship among Blaschke vectors that the obtained formulae in [2, 3] change if parameter ruled surfaces of the spacelike line congruence are not choosed as principle ruled surfaces. Moreover, using the relation among Blaschke vectors, we obtain Manheim's and Liouville's formulae. This new method can be applied to congruences. Thus, we can obtain new formulae in lines space.

• 충청수학회지
• /
• 제29권2호
• /
• pp.229-253
• /
• 2016

As a generalization of (i, j)-weakly m-continuous functions [43], we introduce the notion of weakly M(i, j)-continuous functions and obtain many characterizations and some properties of the functions. We show that the function is a unified form of some functions between m-spaces and certain kinds of weakly continuous functions in bitopological spaces.

• Journal of applied mathematics & informatics
• /
• 제19권1_2호
• /
• pp.363-370
• /
• 2005

In this paper, we obtain a new fixed point theorem in complete probabilistic ${\Delta}$-inner product space. As an example of applications, we utilize the results of this paper to study the existence and uniqueness of solutions for linear Valterra integral equation.

• Korean Journal of Mathematics
• /
• 제25권3호
• /
• pp.437-453
• /
• 2017

A new class of sets, called generalized (${\Lambda}$, b)-closed sets, has been introduced and studied. Also, several properties of generalized (${\Lambda}$, b)-closed sets are investigated. Some characterizations of ${\Lambda}_b$-regular spaces and ${\Lambda}_b$-normal spaces are discussed.

• East Asian mathematical journal
• /
• 제23권2호
• /
• pp.135-149
• /
• 2007

In 1975, Wenger [4] determined the fine spectra of $Ces{\grave{a}}ro$ operator $C_1$ on c, the space of convergent sequences. In [7], the spectrum of the Rhaly operators on $c_0$ and c, under the assumption that ${lim}\limits_{n{\rightarrow}{\infty}}(n+1)a_n\;=\;L\;{\neq}\;0$, has been determined. In this paper the author determine the fine spectra of the Rhaly matrix $R_a$ as an operator on the space c, with the same assumption.

• 호남수학학술지
• /
• 제35권2호
• /
• pp.109-117
• /
• 2013

In the present paper, we utilize the notion of converse commuting mappings due to L$\ddot{u}$ [On common fixed points for converse commuting self-maps on a metric spaces, Acta. Anal. Funct. Appl. 4(3) (2002), 226-228] and prove a common fixed point theorem in Menger space using an implicit relation. We also give an illustrative example to support our main result.

• Kyungpook Mathematical Journal
• /
• 제53권3호
• /
• pp.341-348
• /
• 2013

In this paper, the concept of supra $b$-irresolute maps is introduced and several properties of it is investigated. Furthermore, the notion of supra $b$-connectedness is defined and researched by means of supra $b$-separated sets.

• 대한수학회논문집
• /
• 제18권4호
• /
• pp.669-676
• /
• 2003

In 1989, Rhaly [4] determined the spectrum of Rhaly operator $R_{a}$ on the Hilbert space ${\ell}_2$. In this paper Authors determine the spectrum of the Rhaly matrix $R_{a}$ as an operator on the space bvo with assumption $0\;<\;L\;=\;lim_n(n\;+\;1)a_n\;<\;\infty$.

• 대한수학회보
• /
• 제57권6호
• /
• pp.1581-1590
• /
• 2020

In [1], there are some mistakes in calculations and solutions of differential equations and theorems that appeared in the paper. We here provide correct solutions and theorems.