• Honam Mathematical Journal
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• v.35 no.4
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• pp.809-817
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• 2013

We research properties of a corresponding Cauchy theorem of hyperholomorphic functions in an open set of product complex spaces, in the sense of complex Clifford analysis.

• Honam Mathematical Journal
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• v.40 no.1
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• pp.109-124
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• 2018

In this paper, structure of involution ${\Gamma}$-semihypergroup is introduced and some theorems about this concept are stated and proved. The concept of ${\Gamma}$-hyperideal in involution ${\Gamma}$-semihypergroup is defined and some of their properties are studied. Some results on regular ${\Gamma}^*$-semihypergroups and fuzzy ${\Gamma}^*$-semihypergroups are also provided.

• Communications of the Korean Mathematical Society
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• v.9 no.3
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• pp.513-519
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• 1994

Endomorphism rings of Aritinian modules need not be semiperfect by a result of Camps and Mena [4], which answers in the negative to a question of Crawley and Jonsson[5]. However it was shown by Camps and Dicks[3] that endomorphism rings of a certain class of Artinian modules, we investigate some interesting structures of endormorphism rings of CS-modules.

• Bulletin of the Korean Mathematical Society
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• v.34 no.4
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• pp.509-518
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• 1997

In this paper, we study the developing maps of the Lie groups with left-invariant affinely flat structures. We make some bacis observations on the nature of the developing images and show that the developing map for an incomplete affine structure splits as a product of a covering map of codimension 1 and a diffeomorphism of dimension 1.

• Bulletin of the Korean Mathematical Society
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• v.33 no.4
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• pp.619-629
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• 1996

In studying smooth 4-manifolds the Donaldson invariant has played a central role. In [D1] Donaldson showed that non-vanishing Donaldson invariant of a smooth closed oriented 4-manifold X gives rise to the indecomposability of X. For instance, the complex algebraic suface X cannot decompose to a connected sum $X_1 #X_2$ with both $b_2^+(X_i) > 0$.

• Communications of the Korean Mathematical Society
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• v.27 no.1
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• pp.23-36
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• 2012

Dual monoidal category $\mathcal{C}^*$ of a monoidal functor F : $\mathcal{C}\;{\rightarrow}\;\mathcal{V}$ has been constructed by S. Majid. In this paper, we extend the construction of dual structures for an Ann-functor F : $\mathcal{B}\;{\rightarrow}\;\mathcal{A}$. In particular, when F = $id_{\mathcal{A}}$, then the dual category $\mathcal{A}^*$ is indeed the center of $\mathcal{A}$ an this is a braided Ann-category.

• Communications of the Korean Mathematical Society
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• v.35 no.4
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• pp.1255-1267
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• 2020

The class of isotropic almost complex structures, J_𝛿,𝜎, define a class of Riemannian metrics, g_𝛿,𝜎, on the tangent bundle of a Riemannian manifold which are a generalization of the Sasaki metric. This paper characterizes the metrics g_𝛿,0 using the geometry of tangent bundle. As a by-product, some integrability results will be reported for J_𝛿,𝜎.

• Journal of the Korean Mathematical Society
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• v.41 no.6
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• pp.1035-1047
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• 2004

In this paper, we study the unit tangent sphere bundles T$_1$M(4c) of complex space forms M(4c) with constant holomorphic sectional curvature 4c. In particular, we determine T$_1$M(4c) whose Ricci tensors satisfy the Einstein-like conditions.

• Journal of the Korean Mathematical Society
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• v.40 no.2
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• pp.273-286
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• 2003

Let $F^{\alpha}$G be a twisted group algebra. A subalgebra of $F^{\alpha}$G generated by all class sums of partition P of G is called a projective class algebra in $F^{alpha}$G associated with partition P. In this paper we study various partitions of G determined by actions of certain operator groups on G and construct projective class algebras depending on the actions. With regard to projective class algebras, we investigate structures of associated skew group algebras and fixed group algebras.

• Communications of the Korean Mathematical Society
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• v.22 no.4
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• pp.547-552
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• 2007

The unit interval is not homeomorphic to a self-similar Cantor set in which we studied the dimensions of distribution subsets. However we show that similar results regarding dimensions of the distribution subsets also hold for the unit interval since the distribution subsets have similar structures with those in a self-similar Cantor set.