• 대한수학회보
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• 제43권2호
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• pp.377-387
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• 2006

In this paper, some characterizations of representation for continuous linear functionals on $2{\kappa}$-inner product spaces in terms of best approximations and orthogonalities are given.

• 대한수학회지
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• 제32권4호
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• pp.889-895
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• 1995

Let $H$ be a separable, infinite dimensional, complex Hilbert space and let $L(H)$ denote the algebra of all bounded linear operators on $H$.

• 대한수학회보
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• 제51권2호
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• pp.501-510
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• 2014

We characterize hypergeneralized k-projectors (i.e., $A^k=A^{\dag}$). Also, some representation for the Moore-Penrose inverse of a linear combination of hypergeneralized k-projectors is found and the invertibility for some linear combinations of commuting hypergeneralized k-projectors is considered.

• 대한수학회보
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• 제33권2호
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• pp.213-219
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• 1996

In this note we study the representations on Hilbert space of involutive semigroups, i.e., semigroups endowed with an involutive antiautomorphism. This subject is studied by K. H. Neeb, and some interesting results are ivestigated ([3]).

• 대한수학회지
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• 제33권2호
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• pp.387-397
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• 1996

Let G be a finite group and F be a field of characteristic $p \geq 0$. Let $\Gamma = F^f G$ be a twisted group algebra corresponding to a 2-cocycle $f \in Z^2(G,F^*), where F^* = F - {0}$ is the multiplicative subgroup of F.

• 대한수학회보
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• 제49권6호
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• pp.1335-1348
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• 2012

We prove a Hardy inequality related to Carnot-Carath$\acute{e}$odory distance on H-type groups based on a representation formula on such groups.

• 대한수학회지
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• 제55권3호
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• pp.507-530
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• 2018

It is shown that for a non-unitary twist of a Fuchsian group, which is unitary at the cusps, Eisenstein series converge in some half-plane. It is shown that invariant integral operators provide a spectral decomposition of the space of cusp forms and that Eisenstein series admit a meromorphic continuation.

• 대한수학회논문집
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• 제14권1호
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• pp.157-169
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• 1999

We consider the C\ulcorner-algebra O\ulcorner generated by infinite isometries \ulcorner,\ulcorner, …on Hilbert spaces with the property \ulcorner \ulcorner$\leq$1 for every n$\in$N. We present certain type of representations of C\ulcorner-algerbra O\ulcorner on a separable Hilbert space and study the conditions for irreducibility of these representations.

• 충청수학회지
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• 제18권2호
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• pp.117-129
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• 2005

We give a generalization of bilateral mock theta functions of order eight and show that they are $F_q$-functions. We also give an integral representation for these functions. We give a relation between mock theta functions of the first set and bilateral mock theta functions of the second set.

• 대한수학회논문집
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• 제10권2호
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• pp.275-284
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• 1995

In this paper various G-module structures on M and all possible extensions of M by G will be studied, whence equivalence classes of extensions of M by G and those of extensions which are compatible with the given G-module structures of M will be determined explicitly. Further the difference between extensions and compatible extensions will be pointed out.