• Korean Journal of Mathematics
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• 제11권2호
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• pp.147-153
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• 2003

We investigate some properties on right(resp. left) duo $po$-semigroups.

• 한국수학사학회지
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• 제20권2호
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• pp.109-126
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• 2007

Lobachevskii와 Hadamard는 유럽에서 Euclid의 '원론'에 의한 기하교육으로부터 새로운 형태의 기하교육으로의 전환하는 시기에 기하학 교재를 저술하였다. 본 연구에서는 Lobachevskii의 '기하학'과 Hadamard의 '초등기하학'에서 다루고 있는 삼각형의 합동에 대한 정리들을 조사하고, 이들의 증명 방법들을 분석하며, 직각삼각형의 합동조건의 증명 방법을 우리나라의 수학교과서에 제시된 증명 방법들과 비교하였다.

• Korean Journal of Mathematics
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• 제14권2호
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• pp.241-248
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• 2006

We define a G-fuzzy congruence, which is a generalized fuzzy congruence, and characterize the G-fuzzy congruence generated by a left and right compatible fuzzy relation on a semigroup.

• 대한수학회보
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• 제36권1호
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• pp.139-146
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• 1999

It is known that a right nilpotent congruence $\beta$ on a finite algebra A is also left nilpotent [3]. The question on whether the left nilpotency class of $\beta$ in less than or equal to the right nilpotency class of $\beta$is still open. In this paper we find an upper limit for the left nilpotency class of $\beta$. In addition, under the assumption that 1 $\in$ typ{A}, we show that $(\beta]^k=[\beta)^k$ for all k$\geq$1. Thus the left and right nilpotency classes of $\beta$ are the same in this case.

• 충청수학회지
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• 제24권3호
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• pp.449-456
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• 2011

In this paper, we considered the congruence relation, isomorphism and obtained some properties of HS-algebras.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제4권2호
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• pp.131-135
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• 1997

We give the relation between the semilattice congruence N and the set of prime ideals of the ordered $\Gamma$-semigroup M.

• 대한수학회논문집
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• 제19권1호
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• pp.1-10
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• 2004

We here consider necessary and sufficient conditions for a completely right injective semigroup S whose lattice Ｌ(S) of right congruences on S is semiatomic. These are preceded by a number of results on the characterization of a semigroup S in which every automaton over S is injective(called a completely right injective semigroup).

• 한국수학교육학회지시리즈A:수학교육
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• 제46권3호
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• pp.273-292
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• 2007

The purpose of this study was to find out how second, fourth and sixth graders understood the main contents related to spatial sense in the Seventh National Mathematics Curriculum. For this purpose, this study examined students' understanding of the main contents of congruence transformation (slide, flip, turn), mirror symmetry, cubes, congruence and symmetry. An investigation was conducted and the subjects included 483 students. The main results are as follows. First, with regards to congruence transformation, whereas students had high percentages of correct answers on questions concerning slide, they had lower percentages on questions concerning turn. Percentages of correct answers on flip questions had significant differences among the three grades. In addition, most students experienced difficulties in describing the changes of shapes. Second, students understood the fact that the right and the left of an image in a mirror are exchanged, but they had poor overall understanding of mirror symmetry. The more complicated the cubes, the lower percentages of correct answers. Third, students had a good understanding of congruences, but they had difficulties in finding out congruent figures. Lastly, they had a poor understanding of symmetry and, in particular, didn't distinguish a symmetric figure of a line from a symmetric figure of a point.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.449-458
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• 2002

We shall give a gereralization for a new right congruence induced by right congruences on S and right ideals of S and discuss the radicals associated with automata. Also we shall discuss the relationship between the collection of all right ideals in S and the collection of all right congruences on S.

• 한국지능시스템학회논문지
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• 제17권1호
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• pp.100-111
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• 2007

We introduce the concept of intuitionistic fuzzy G-equivalence relations (congruence), and we obtain some results. Furthermore, we prove that $IFC_G(K)$ is isomorphic to $IFN^*(K)$ for any group K. Also, we prove that($IFC_{G,({\lambda},{\mu})}/{\sim},\;*$) and ($IFNG_{({\lambda},{\mu})}(K),\;{\circ}$) are isomorphic.