• Journal of the Chungcheong Mathematical Society
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• v.23 no.4
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• pp.853-860
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• 2010

A class invariant is the value of a modular function that generates a ring class field of an imaginary quadratic number field such as the singular moduli of level 1. In this paper, using Shimura Reciprocity Law, we compute the Galois actions of a class invariant from a generalized Weber function $g_2$ over quadratic number fields with discriminant $D{\equiv}-3$ (mod 36).

• Communications of the Korean Mathematical Society
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• v.17 no.2
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• pp.253-260
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• 2002

For an outer action $\alpha$ of a finite group G on a factor M, it was proved that H is a, normal subgroup of G if and only if there exists a finite group F and an outer action $\beta$ of F on the crossed product algebra M $\times$$_{\alpha}$ G = (M $\times$$_{\alpha}$ F. We generalize this to infinite group actions. For an outer action $\alpha$ of a discrete group, we obtain a Galois correspondence for crossed product algebras related to normal subgroups. When $\alpha$ satisfies a certain condition, we also obtain a Galois correspondence for fixed point algebras. Furthermore, for a minimal action $\alpha$ of a compact group G and a closed normal subgroup H, we prove $M^{G}$ = ( $M^{H}$)$^{{beta}(G/H)}$for a minimal action $\beta$ of G/H on $M^{H}$.f G/H on $M^{H}$.TEX> H/.

• Honam Mathematical Journal
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• v.40 no.2
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• pp.281-291
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• 2018

We associate a positive integer n and a subgroup H of the group $({\mathbb{Z}}/n{\mathbb{Z}})^{\times}$ with a polynomial $J_n,H(x)$, which is called the Galois polynomial. It turns out that $J_n,H(x)$ is a polynomial with integer coefficients for any n and H. In this paper, we provide an equivalent condition for a subgroup H to provide the Galois polynomial which is irreducible over ${\mathbb{Q}}$ in the case of $n=p^{e_1}_1{\cdots}p^{e_r}_r$ (prime decomposition) with all $e_i{\geq}2$.

• Bulletin of the Korean Mathematical Society
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• v.40 no.3
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• pp.537-544
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• 2003

The non-existence is proved of continuous irreducible representations p : Gal(Q/Q) \longrightarrow GL$_2$(F$_{p}$) with Artin conductor N outside p for a few small values of p and N.N.

• Bulletin of the Korean Mathematical Society
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• v.44 no.1
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• pp.173-176
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• 2007

The non-existence is proved of four-dimensional mod 2 semisimple representations of Gal ($\=\mathbb{Q}/\mathbb{Q}$) which are unramified outside 2.

• Korean Journal of Mathematics
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• v.20 no.2
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• pp.193-212
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• 2012

We investigate the properties of fuzzy connections. We find generating functions which induce fuzzy connections. In particular, we show that their connections relate to fuzzy relations.

• Korean Journal of Mathematics
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• v.21 no.3
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• pp.351-363
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• 2013

We study the properties of weak extended order algebras having adjoint pairs (triples) or Galois pairs. In particular, we investigate the various laws on weak extended order algebras.

• Korean Journal of Mathematics
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• v.20 no.1
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• pp.61-75
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• 2012

We investigate the properties of various frames and connections on partially ordered sets. In particular, we study the relations between various connections and various frames.

• Journal of the Chungcheong Mathematical Society
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• v.22 no.3
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• pp.497-506
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• 2009

This work studies about the composition polynomial f(g(x)) that preserves certain properties of f(x) and g(x). We shall investigate necessary and sufficient conditions of f(x) and g(x) to be f(g(x)) is separable, solvable by radical or split completely. And we find relationship of Galois groups of f(g(x)), f(x) and of g(x).

• Korean Journal of Mathematics
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• v.21 no.1
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• pp.63-73
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• 2013

We study the properties of extended order algebras. In particular, we investigate the properties of adjoint, Galois pair in commutative extended-order algebras.