• Journal of the Korean Mathematical Society
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• v.45 no.6
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• pp.1725-1740
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• 2008

In this paper, we introduce a fixed point index of weakly inward 1-set-contraction mappings. With the aid of the new index, we obtain some new fixed point theorems, nonzero fixed point theorems and multiple positive fixed points for this class of mappings. As an application of nonzero fixed point theorems, we discuss an eigenvalue problem.

• Communications of the Korean Mathematical Society
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• v.24 no.2
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• pp.247-263
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• 2009

In this paper we use degree and index theory to present new applicable fixed point theory for permissible maps.

• Journal of the Korean Mathematical Society
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• v.34 no.1
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• pp.237-245
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• 1997

The fixed point index plays an important role in solving the positive solutions of nonlinear equations in ordered Banach spaces ([7], [10], [11], [14], [15]). Many authors have studied the existence problems of positive solutions of nonlinear equations for nonlinear mappings ([1]-[5], [7], [9], [10], [14], [15]).

• Journal of the Korean Mathematical Society
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• v.36 no.5
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• pp.911-921
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• 1999

We define the coincidence index of pairs of maps p, f : $\widetilde{X}$ $\rightarrow$ X where p is a covering of a polyhedron X. We use a polyhedral transversality Theorem due to T. Plavchak. When p=identity we get the classical fixed point index of self map of polyhedra without using homology.

• East Asian mathematical journal
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• v.36 no.5
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• pp.593-604
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• 2020

Let the circle act on a compact oriented manifold with a discrete fixed point set. At each fixed point, there are positive integers called weights, which describe the local action of S¹ near the fixed point. In this paper, we provide the author's original proof that only uses the Atiyah-Singer index formula for the classification of the weights at the fixed points if the dimension of the manifold is 4 and there are at most 4 fixed points, which made the author possible to give a classification for any finite number of fixed points.

• East Asian mathematical journal
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• v.24 no.1
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• pp.97-103
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• 2008

New fixed point theorems for permissible maps between $Fr{\acute{e}}chet$ spaces are presented. The proof relies on index theory developed by Dzedzej and on viewing a $Fr{\acute{e}}chet$ space as the projective limit of a sequence of Banach spaces.

• Communications of the Korean Mathematical Society
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• v.13 no.1
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• pp.29-36
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• 1998

We show that if M is a $II_1$-factor and a countable discrete group G acts outerly on M then Jones' index $[M:M^G]$ of a pair of $II_1^-factors is equal to the order $\mid$G$\mid$ of G. It is also shown that for a subgroup H of G Jones' index $[M^H:M^G]$ is equal to the group index [G:H] under certain conditions.

• East Asian mathematical journal
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• v.39 no.1
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• pp.43-50
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• 2023

This paper is concerned with the existence of positive solutions to the second order differential systems with strongly coupled integral boundary value conditions. The fixed point index theorems are used for the main results.

• Bulletin of the Korean Mathematical Society
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• v.49 no.4
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• pp.815-827
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• 2012

The existence of $n$ positive solutions is established for second order multi-point boundary value problem at resonance where $n$ is an arbitrary natural number. The proof is based on a theory of fixed point index for A-proper semilinear operators defined on cones due to Cremins.

• Bulletin of the Korean Mathematical Society
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• v.38 no.4
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• pp.643-655
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• 2001

We discuss the existence of positive solutions to a certain nonlinear elliptic system representing a competition interaction with self-diffusion. The method used here is a fixed point index theory in a positive cone. We give a sufficient condition for the existence of positive solutions.