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Related papers: A Combinatorial Study of the Fixed Point Index

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We give a quick survey of the various fixed point theorems in computability theory, partial combinatory algebra, and the theory of numberings, as well as generalizations based on those. We also point out several open problems connected to…

Logic · Mathematics 2024-02-06 Sebastiaan A. Terwijn

We develop a geometric framework that unifies several different combinatorial fixed-point theorems related to Tucker's lemma and Sperner's lemma, showing them to be different geometric manifestations of the same topological phenomena. In…

Combinatorics · Mathematics 2013-05-28 Elyot Grant , Will Ma

An integer-valued fixed point index for compositions of acyclic multivalued maps is constructed. This integer-valued fixed point index has the properties: additivity, homotoy invariance, normalization, commutativity, multiplicativity. The…

General Topology · Mathematics 2007-05-23 E. G. Sklyarenko , G. Skordev

The purpose of this paper is to present some multidimensional fixed-point theorems and their applications. For this, we provide a multidimensional fixed point theorem and then using this theorem we prove the existence and uniqueness of a…

Functional Analysis · Mathematics 2021-07-28 H. Akhadkulov , S. Akhatkulov , T. Y. Ying , R. Tilavov

This paper presents new approaches to the fixed point property for nonexpansive mappings in L^1 spaces. While it is well-known that L^1 fails the fixed point property in general, we provide a complete and self-contained proof that…

Functional Analysis · Mathematics 2025-09-15 Faruk Alpay , Hamdi Alakkad

This paper discusses discrete-time maps of the form $x(k + 1) = F(x(k))$, focussing on equilibrium points of such maps. Under some circumstances, Lefschetz fixed-point theory can be used to establish the existence of a single locally…

Systems and Control · Electrical Eng. & Systems 2024-10-25 Brian D. O. Anderson , Mengbin Ye

It is often useful to perform integration over learned functions represented by neural networks. However, this integration is usually performed numerically, as analytical integration over learned functions (especially neural networks) is…

Machine Learning · Computer Science 2023-12-27 Ryan Kortvelesy

We survey several applications of fixed point theorems in the theory of invariant subspaces. The general idea is that a fixed point theorem applied to a suitable map yields the existence of invariant subspaces for an operator on a Banach…

Operator Algebras · Mathematics 2012-10-23 Rafa Espínola , Miguel Lacruz

We characterize the sequences of fixed point indices $\{i(f^n, p)\}_{n\ge 1}$ of fixed points that are isolated as an invariant set and continuous maps in the plane. In particular, we prove that the sequence is periodic and $i(f^n, p) \le…

Dynamical Systems · Mathematics 2016-05-30 Luis Hernandez-Corbato , Francisco R. Ruiz del Portal

The goal of this paper is to promote the use of fixed point strategies in data science by showing that they provide a simplifying and unifying framework to model, analyze, and solve a great variety of problems. They are seen to constitute a…

Optimization and Control · Mathematics 2021-08-11 Patrick L. Combettes , Jean-Christophe Pesquet

Using the theory of fixed point index, we discuss the existence and multiplicity of non-negative solutions of a wide class of boundary value problems with coupled nonlinear boundary conditions. Our approach is fairly general and covers a…

Classical Analysis and ODEs · Mathematics 2014-08-14 Gennaro Infante , Paolamaria Pietramala

The classical Lefschetz fixed point theorem states that the number of fixed points, counted with multiplicity $\pm 1$, of a smooth map $f$ from a manifold $M$ to itself can be calculated as the alternating sum $\sum (-1)^k \textrm{ tr }…

Algebraic Topology · Mathematics 2022-07-04 Loring W. Tu

Diversities have been recently introduced as a generalization of metrics for which a rich tight span theory could be stated. In this work we take up a number of questions about hyperconvexity, diversities and fixed points of nonexpansive…

Metric Geometry · Mathematics 2016-10-05 Bozena Piatek , Rafa Espinola

For a compact Lie group G, we use G-equivariant Poincar\'e duality for ordinary RO(G)-graded homology to define an equivariant intersection product, the dual of the equivariant cup product. Using this, we give a homological construction of…

Algebraic Topology · Mathematics 2013-07-23 Philipp Wruck

Let X be a locally compact space with a continuous proper action of a locally compact group G. Assuming that X satisfies a certain kind of duality in equivariant bivariant Kasparov theory, we can enrich the classical construction of…

K-Theory and Homology · Mathematics 2015-10-23 Heath Emerson , Ralf Meyer

In this paper, we define concept of approximate fixed point property of a function and a set in intuitionistic fuzzy normed space. Furthermore, we give intuitionistic fuzzy version of some class of maps used in fixed point theory and…

Functional Analysis · Mathematics 2015-09-10 Müzeyyen Ertürk , Vatan Karakaya , M. Mursaleem

We introduce the universal functorial equivariant Lefschetz invariant for endomorphisms of finite proper G-CW-complexes, where G is a discrete group. We use K_0 of the category of "phi-endomorphisms of finitely generated free…

Algebraic Topology · Mathematics 2007-05-23 Julia Weber

Suppose one is given a discrete group G, a cocompact proper G-manifold M, and a G-self-map f of M. Then we introduce the equivariant Lefschetz class of f, which is globally defined in terms of cellular chain complexes, and the local…

Algebraic Topology · Mathematics 2011-04-14 Wolfgang Lueck , Jonathan Rosenberg

In this paper, locally Lipschitz, regular functions are utilized to identify and remove infeasible directions from set-valued maps that define differential inclusions. The resulting reduced set-valued map is point-wise smaller (in the sense…

Systems and Control · Computer Science 2021-07-07 Rushikesh Kamalapurkar , Warren E. Dixon , Andrew R. Teel

We introduce new Lagrangian cycles which encode local contributions of Lefschetz numbers of constructible sheaves into geometric objects. We study their functorial properties and apply them to Lefschetz fixed point formulas with…

Algebraic Geometry · Mathematics 2008-12-25 Yutaka Matsui , Kiyoshi Takeuchi