• Honam Mathematical Journal
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• v.9 no.1
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• pp.135-147
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• 1987

It is well known that there are two ways to define Chern classes of complex vector bundles. One gives the definition of Chern classes by the five axioms ([2]. [3], [4]). and an other defines Chern classes with the associated projective space bundle of a given bundle ([1]. [5]). The purpose of this paper is to describe the latter way in detail and to give new proofs of that our Chern classes satisfy the five axioms with respect to Chern classes (for example Theorem 5).

• Journal of the Korean Mathematical Society
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• v.61 no.1
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• pp.133-147
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• 2024

Let G = (V, E) be a connected finite graph. We study the existence of solutions for the following generalized Chern-Simons equation on G $${\Delta}u={\lambda}e^u(e^u-1)^5+4{\pi}\sum_{s=1}^{N}\delta_{ps}$$, where λ > 0, δ_ps is the Dirac mass at the vertex p_s, and p₁, p₂, . . . , p_N are arbitrarily chosen distinct vertices on the graph. We show that there exists a critical value $\hat{\lambda}$ such that when λ > $\hat{\lambda}$, the generalized Chern-Simons equation has at least two solutions, when λ = $\hat{\lambda}$, the generalized Chern-Simons equation has a solution, and when λ < $\hat{\lambda}$, the generalized Chern-Simons equation has no solution.

• East Asian mathematical journal
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• v.37 no.5
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• pp.591-598
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• 2021

In this paper we study the Cauchy problem for the Chern-Simons gauged O(3) sigma model. We prove the local existence of solutions with low regularity initial data, observing null forms of the system and applying bilinear estimates for wave-Sobolev space H^{s, b}.

• Communications of the Korean Mathematical Society
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• v.33 no.3
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• pp.871-888
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• 2018

We study the nonrelativistic limit of the Chern-Simons-Dirac system on ${\mathbb{R}}^{1+2}$. As the light speed c goes to infinity, we first prove that there exists an uniform existence interval [0, T] for the family of solutions ${\psi}^c$ corresponding to the initial data for the Dirac spinor ${\psi}_0^c$ which is bounded in $H^s$ for ${\frac{1}{2}}$ < s < 1. Next we show that if the initial data ${\psi}_0^c$ converges to a spinor with one of upper or lower component zero in $H^s$, then the Dirac spinor field converges, modulo a phase correction, to a solution of a linear $Schr{\ddot{o}}dinger$ equation in C([0, T]; $H^{s^{\prime}}$) for s' < s.

• The Journal of Natural Sciences
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• v.10 no.1
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• pp.13-16
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• 1998

Every complex vector bundle over $S^1$ splits sum of line bundle and the first Chern class classify complex line bundle. This implies every complex vector bundle over $S^1$ is trivial. In this paper, we show the existence of some nontrivial complex vector bundle over $S^1$ in the equivariant case.

• Korean Journal of Mathematics
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• v.17 no.1
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• pp.1-13
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• 2009

For an isometric immersion $f:M{\rightarrow}{\bar{M}}$ of Finsler manifolds M into $\bar{M}$, we compare the intrinsic Chern connection on M and the induced connection on M: We find the conditions for them to coincide and generalize the equations of Gauss, Ricci and Codazzi to Finsler submanifolds. In case the ambient space is a locally Minkowskian Finsler manifold, we simplify the above equations.

• Bulletin of the Korean Mathematical Society
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• v.25 no.2
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• pp.261-266
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• 1988

• Communications of the Korean Mathematical Society
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• v.4 no.2
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• pp.289-295
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• 1989

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.194.1-194.1
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• 2007

• International Journal of Human Ecology
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• v.6 no.1
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• pp.17-28
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• 2005

This study examines factors determining contemporary Chinese households' food away from home (FAFH) expenditures using Becker's household production theory. Data came from the 2000 urban household survey in Guangdong Province, collected by National Bureau of Statistics (NBS) of China. It was revealed that the contemporary urban Chinese wives also substitute their household work by time-saving product, FAFH, as Becker's household production theory postulated. This suggests the important role of time-value (opportunity cost) in determining household FAFH expenditure across the cultures.