• 대한수학회논문집
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• 제34권1호
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• pp.351-359
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• 2019

In this paper, we introduce a modification of extremally disconnected spaces which is said to be m-extremally disconnected. And we obtain many characterizations of m-extremally disconnected spaces. The concepts of ${\ast}$-extremally disconnected spaces, ${\ast}$-hyperconnected spaces, and generalized hyperconnectedness are as examples for this paper.

• 대한수학회지
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• 제58권1호
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• pp.173-205
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• 2021

The spherical buildings associated with absolutely simple algebraic groups of relative rank 2 are all Moufang polygons. Tits polygons are a more general class of geometric structures that includes Moufang polygons as a special case. Dagger-sharp Tits n-gons exist only for n = 3, 4, 6 and 8. Moufang octagons were classified by Tits. We show here that there are no dagger-sharp Tits octagons that are not Moufang. As part of the proof it is shown that the same conclusion holds for a certain class of dagger-sharp Tits quadrangles.

• 대한수학회지
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• 제60권1호
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• pp.227-253
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• 2023

In this article, we generalize the results discussed in [6] by introducing a genus to generic fibers of Lefschetz fibrations. That is, we give families of relations in the mapping class groups of genus-1 surfaces with boundaries that represent rational homology disk smoothings of weighted homogeneous surface singularities whose resolution graphs are 3-legged with a bad central vertex.

• 충청수학회지
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• 제23권4호
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• pp.885-892
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• 2010

In this paper we study the structures and properties of a single cycle T-finction, whose theory has been lately proposed by Klimov and Shamir. Any cryptographic system based on T-functions may be insecure. Some of the TSC-series stream ciphers have been successfully attacked by some attacks. So it is important to analyze every aspect of a single cycle T-function. We study some properties on a single cycle T-function and we show some examples are single cycle T-functions by these properties, whose proof is easier than existing methods.

• 대한수학회논문집
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• 제38권2호
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• pp.575-588
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• 2023

In the present paper, we consider a kind of generalized hyperbolic geometric flow which has a gradient form. Firstly, we establish the existence and uniqueness for the solution of this flow on an n-dimensional closed Riemannian manifold. Then, we give the evolution of some geometric structures of the manifold along this flow.

• 대한수학회지
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• 제61권1호
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• pp.161-181
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• 2024

We describe the moduli space of Higgs pairs on an irreducible nodal curve of arithmetic genus one and its geometric structures in terms of the Hitchin map and a flat degeneration of the moduli space of Higgs bundles on an elliptic curve.

• 대한수학회논문집
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• 제39권2호
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• pp.493-511
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• 2024

We introduce invariant rigged null hypersurfaces of indefinite almost contact manifolds, by paying attention to those of indefinite nearly α-Sasakian manifolds. We prove that, under some conditions, there exist leaves of the integrable screen distribution of the ambient manifolds admitting nearly α-Sasakian structures.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제27권1호
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• pp.151-156
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• 2024

Mathematics Classrooms that Students Love, Grade 1: Numbers and Operations is a book that reviews student-centered educational strategies in mathematics, contrasting the teacher-centered approach. The book included lesson plans, transcriptions, and annotated comments for imperative instructional practices. Drawing from a range of effective instructional practices, it explores how student engagement and enjoyment in mathematics can be fostered through innovative lesson structures, activities, and discussions.

• 대한수학회논문집
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• 제39권3호
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• pp.673-692
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• 2024

In this work, an alternative fashion of the multi-Jensen is introduced. The structures of the multi-Jensen and the multi-Euler-Lagrange-Jensen mappings are described. In other words, the system of n equations defining each of the mentioned mappings is unified as a single equation. Furthermore, by applying a fixed point theorem, the Hyers-Ulam stability for the multi-Euler-Lagrange-Jensen mappings in the setting of Banach spaces is established. An appropriate counterexample is supplied to invalidate the results in the case of singularity for multiadditive mappings.

• 한국학교수학회논문집
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• 제12권2호
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• pp.309-325
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• 2009

본 연구의 목적은 미국의 개정 교과서(reform curriculum) 중 하나인 CPMP 교과서 (코스1-코스3)와 한국의 교과서(중3-고2)를 사전에 설정한 비교 준거를 토대로 비교분석하여 두 교과서 및 교수 학습 환경에서의 차이점을 토대로 한국의 수학과 교육과정 및 수학 교과서의 질적 수준을 향상시킬 수 있는 요인을 찾아보는 데 있다. 비교 준거는 두 교과서의 구성상의 특징인 내용의 위계 및 지도계열의 설정, 수업의 방법적 접근 방법, 교수 학습 환경으로 설정하였다. 연구 결과, 한국의 교과서는 수학의 구조 또는 계통성, 수학 내적 연결망을 강조하여 수학의 구조를 효율적으로 전달할 수 있는 교수 방법에 맞게 구성되어 있고, CPMP 교과서는 수학의 계통성과 더불어 수학외적 연결망과 통합 연결망을 강조하여 학생들이 수학적 개념을 보다 다양한 맥락 속에서 탐구 활동을 통하여 학습할 수 있도록 구성되었다. 또, 한국 교과서의 경우 엄격한 개념의 일반화를 중요하게 여겨 논리적이고 형식적인 내용 전개 과정을 강조한 반면, CPMP 교과서는 비형식적 사고 과정 또는 직관을 중요하게 여겨 실생활 소재를 포함한 다양한 맥락 속에서 수학적 개념의 탐구와 문제 해결을 보다 강조하였다. 각 교과서가 사용되는 교수 학습 환경은 한국의 경우 주로 유의미 설명 방법으로 수업이 진행되었고 보조 학습 도구로 교구 및 학습지가 활용되었다. 반면, CPMP 교과서를 사용하는 교실에서는 학생들의 의사소통 활동을 강조한 모둠 활동과 그래픽 계산기의 사용이 강조되었다.