• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.376-386
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• 1995

Designs for polynomial approximation to the unknown response function are considered. Optimality criteria are monotone functions of the mean squared error matrix of the least squares estimator. They correspond to the classical A-, D-, G- and Q-optimalities. Optimal first order designs are chosen from the invariant designs and then compared with optimal second order designs.

• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.755-761
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• 2016

Let A be an abelian variety over a global field K. We show that, in "many" cases, Chen-Kuan's invariant M(A[n]), that is the average number of n-torsion points of A over various residue fields of K, has the minimal possible value.

• Journal of the Chungcheong Mathematical Society
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• v.1 no.1
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• pp.85-90
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• 1988

We develope a signature invariant for odd higher dimensional links. This signature has an advantage that it is defined as a G-signature for a non-abelian group G so that it can distinguish two links whose different were not detected by other invariants defined on commutative set-ups.

• Communications of the Korean Mathematical Society
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• v.36 no.4
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• pp.829-833
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• 2021

We investigate the Möbius transformation action of PSL(2, ℝ) on the set of mutually distinct ordered triple points of ℝ ∪ {∞}.

• Bulletin of the Korean Mathematical Society
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• v.58 no.5
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• pp.1097-1107
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• 2021

In this paper, we focus on the Hopf invariant and give an alternative proof for the unboundedness of stabilization heights of fiber surfaces, which was firstly proved by Baader and Misev.

• Kyungpook Mathematical Journal
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• v.61 no.2
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• pp.395-408
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• 2021

The object of the present paper is to study f-biharmonic submanifolds of three dimensional trans-Sasakian manifolds. We find some necessary and sufficient conditions for such submanifolds to be f-biharmonic.

• Bulletin of the Korean Mathematical Society
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• v.58 no.3
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• pp.699-710
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• 2021

In this paper, we study various connections of local spectral properties, invariant subspaces, and spectra when an operator S in 𝓛(𝓗) is an ampliation quasiaffine transform of an operator T in 𝓛(𝓗).

• Korean Journal of Mathematics
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• v.29 no.2
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• pp.425-434
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• 2021

The object of the present paper is to deduce some important results on generic submanifolds and generic product of trans-Sasakian manifolds with concurrent vector fields.

• Korean Journal of Mathematics
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• v.30 no.1
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• pp.175-185
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• 2022

The purpose of this paper is to study invariant submanifolds of a Lorentzian para Kenmotsu manifold. We obtain the necessary and sufficient conditions for an invariant submanifold of a Lorentzian para Kenmotsu manifold to be totally geodesic. Finally, a non-trivial example is built in order to verify our main results.

• Communications of the Korean Mathematical Society
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• v.38 no.1
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• pp.195-203
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• 2023

Special examples of harmonic manifolds that are not symmetric, proving that the conjecture posed by Lichnerowicz fails in the non-compact case have been intensively studied. We completely classify homogeneous structures on Damek-Ricci spaces equipped with the left invariant metric.