• Journal of the Korean Mathematical Society
• /
• v.33 no.4
• /
• pp.735-745
• /
• 1996

This is the sequel to our paper "On projective representations of a group and its subgroups I" [4]. In Section 4[4] we proved some global properties on regularity condition. The purpose of this paper is to study local properties, that is, we shall ask how the regularity condition on subgroups is related to that on group. Throughout the paper we use the same notations as in [4].as in [4].

• Communications of the Korean Mathematical Society
• /
• v.16 no.2
• /
• pp.265-275
• /
• 2001

In the previous paper we studied n-dimensional CR-submanifolds of (n-1) CR-dimension immersed in a complex projective space CP(sup)(n+p)/2, and especially determined such submanifolds under curvature conditions related to vertical direction; In the present article we determine such submanifolds under curvature conditions related to horizontal directions.

• Journal of the Korean Mathematical Society
• /
• v.40 no.4
• /
• pp.595-607
• /
• 2003

In the previous paper [6], the author constructed hyperbolic hypersurfaces of degree $2^{n}$ in the n-dimensional complex projective space for every $n\;\geq\;3$. The purpose of this paper is to give some improvement of this result and to show some general methods of constructions of hyperbolic hypersurfaces of higher degree, which enable us to construct hyperbolic hypersurfaces of degree d in the n-dimensional complex projective space for every $d\;\geq\;2\;{\times}\;6^{n}$.

• Bulletin of the Korean Mathematical Society
• /
• v.40 no.4
• /
• pp.613-631
• /
• 2003

The purpose of this paper is to study n-dimensional QR-submanifolds of (p - 1) QR-dimension in a quaternionic projective space $QP^{(n+p)/4}$ and especially to determine such submanifolds under the curvature conditions appeared in (5.1) and (5.2).

• Journal of the Korean Mathematical Society
• /
• v.39 no.6
• /
• pp.821-879
• /
• 2002

Let U, V and W be complex vector spaces of dimensions 3, 3 and 4 respectively. The reductive algebraic group G = PGL(U) $\times$ PGL(W) $\times$ PGL(W) acts linearly on the projective tensor product space (equation omitted). In this paper, we show that the G-equivalence classes of the projective tensors are in one-to-one correspondence with the PGL(3)-equivalence classes of unordered configurations of six points on the projective plane.

• Bulletin of the Korean Mathematical Society
• /
• v.38 no.3
• /
• pp.575-586
• /
• 2001

The purpose of this paper is to study n-dimensional CR-submanifolds of (n-1) CR-dimension immersed in a complex projective space $CP^{(n+p)/2}$, and especially to determine such submanifolds under some curvature conditions.

• Journal of the Korean Statistical Society
• /
• v.35 no.1
• /
• pp.49-61
• /
• 2006

Wu et al. (1992) constructed some general classes of tight asymmetric orthogonal arrays of strength 2 using the method of grouping. Rains et al. (2002) obtained asymmetric orthogonal arrays of strength 2 using the concept of mixed spread in finite projective geometry. In this paper, we obtain some new tight asymmetric orthogonal arrays of strength 2 using the concept of mixed partition in finite projective geometry.

• The Pure and Applied Mathematics
• /
• v.7 no.1
• /
• pp.7-18
• /
• 2000

Let M be an n-dimensional CR submanifold CR dimension n - l of a complex projective space M. We characterize M of $\bar{M}$ in terms of an estimations of the length of the derivative of Ricci tensor of the length of Ricci tensor.

• The Pure and Applied Mathematics
• /
• v.11 no.3
• /
• pp.197-206
• /
• 2004

We obtain some characterizations of a pseudo Ricci-parallel real hypersurface in a quaternionic projective space $QP^{n}$ and find the condition that M is locally congruent to a geodesic hypersphere of $QP^{n}$ .

• Communications of the Korean Mathematical Society
• /
• v.18 no.1
• /
• pp.75-85
• /
• 2003

Let M be 3 Semi-invariant submanifold of codimension 3 with lift-flat normal connection in a complex projective space. Further, if the mean curvature of M is constant, then we prove that M is a real hypersurface of a complex projective space of codimension 2 in the ambient space.