• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.3
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• pp.45-51
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• 1980

In this paper, a method for constructing Galois switching functions is presented. Single variable Galois switching function is constructed at fi tost by developing Lagrange's Interpolating formula into polynomial forms and then the constructing theory for two variables is driveloped. With these developed theory, multitle-variable Galois switching functions are constructed. Some examples for illustrating the theory are adopted from the existing papers and the results quite agree with the ones in the other papers.

• Communications of the Korean Mathematical Society
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• v.14 no.1
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• pp.99-110
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• 1999

We apply sector theory to obtain some characterization on Gaois groups for subfactors. As an example of a non-irreducible inclusion of small index, a locally trivial inclusion arising from an automorphism is considered and its Galois group is completely determined by using sector theory.

• Journal of the Korean Mathematical Society
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• v.32 no.2
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• pp.265-277
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• 1995

In [9], we gave a very explicit description of the injective envelope of an arbitray simple module over a polynomial ring $K[X_1, \ldots, X_n]$ over a field K in indeterminates $X_1, \ldots, X_n$. This paper presents another approach to give a description.

• Communications of Mathematical Education
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• v.31 no.3
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• pp.279-290
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• 2017

This study proposes a self learning material for understanding the key contents of Galois theory. This material is for teachers who have learned algebraic structures like group, field, and vector space which are related with Galois theory but do not clearly understand how algebraic structures are related with the solvability of polynomials and school mathematics. This material is likely to help them to overcome such difficulties. Even though proposed material is used mainly for self learning, the teachers may be helped once or twice by some professionals. In this article, two expressions 'solvability of polynomial' and 'solvability of equation' have the same meaning and 'teacher' means in-service mathematics teacher.

• Korean Journal of Mathematics
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• v.24 no.3
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• pp.567-572
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• 2016

Quadratic residue codes are cyclic codes of prime length n defined over a finite field ${\mathbb{F}}_{p^e}$, where $p^e$ is a quadratic residue mod n. They comprise a very important family of codes. In this article we introduce the generalization of quadratic residue codes defined over Galois rings using the Galois theory.

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.657-663
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• 2005

In this paper, we consider groups of permutations S on a set A acting on subsets X of A. In particular, we show that if $X_2{\subseteq}X_1{\subseteq}A$ and Y is an S-normal extension of $X_2 in X_1$, then the Galois group $G_{S}(X_1/Y){\;}of{\;}X_1{\;}over{\;}X_2$ relative to S is an S-closed subgroup of $G_{S}(X_1/X_2)$ in the setting of a Galois theory (correspondence) for this situation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1774-1779
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• 2005

This paper propose the design method of the constructing the digital logic systems over galois fields using by the galois field decision diagram(GFDD) that is based on the graph theory. The proposed design method is as following. First of all, we discuss the mathematical properties of the galois fields and the basic properties of the graph theory. After we discuss the operational domain and the functional domain, we obtain the transformation matrixes, $\psi$GF(P)(1) and $\xi$GF(P)(1), in the case of one variable, that easily manipulate the relationship between two domains. And we extend above transformation matrixes to n-variable case, we obtain $\psi$GF(P)(1) and $\xi$GF(P)(1). We discuss the Reed-Muller expansion in order to obtain the digital switching functions of the P-valued single variable. And for the purpose of the extend above Reed-Muller expansion to more two variables, we describe the Kronecker product arithmetic operation.

• Journal of the Korean Mathematical Society
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• v.44 no.1
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• pp.199-210
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• 2007

Given a field K and a finite group G, it is a very interesting problem, although very difficult, to find all Galois extensions over K whose Galois group is isomorphic to G. In this paper, we prepare a theoretical background to study this type of problem when G is the Mathieu group $M_{24}$ and K is a field of characteristic two.

• Communications of the Korean Mathematical Society
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• v.32 no.1
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• pp.1-6
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• 2017

In this paper, the fundamental theorem of Galois Theory is used to generalize cyclotomic polynomials and construct irreducible polynomials associated with the n-th primitive roots of unity.

• East Asian mathematical journal
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• v.38 no.5
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• pp.583-591
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• 2022

Let K be an imaginary quadratic field and 𝒪 be an order in K. Let H_𝒪 be the ring class field of 𝒪. Furthermore, for a positive integer N, let K_𝒪,N be the ray class field modulo N𝒪 of 𝒪. When the discriminant of 𝒪 is different from -3 and -4, we construct an extended form class group which is isomorphic to the Galois group Gal(K_𝒪,N/H_𝒪) and describe its Galois action on K_𝒪,N in a concrete way.