Fixed points of parameterized perturbations

Fixed Points of Parameterized Perturbations

Let X be a convex subset of a locally convex topological vector space, let U ⊂ X be open with U compact, let F : U → X be an upper semicontinuous convex valued correspondence with no fixed points in U \U , let P be a compact absolute neighborhood retract, and let ρ : U → P be a continuous function. We show that if the fixed point index of F is not zero, then there is a neighborhood V of F in th...

Fixed Points, Stability, and Harmless Perturbations

Much has been written about systems in which each constant is a solution and each solution approaches a constant. It is a small step to conjecture that functions promoting such behavior constitute harmless perturbations of stable equations. That idea leads to a new way of avoiding delay terms in a functional-differential equation. In this paper we use fixed point theory to show that such a conj...

Continuity properties and sensitivity analysis of parameterized fixed points and approximate fixed points

In this paper we consider continuity of the set of fixed points and approximate fixed points for parameterized set-valued mappings. Continuity properties are provided for the fixed points of general multivalued mappings, with additional results shown for contraction mappings. Further analysis is provided for the continuity of the approximate fixed points of set-valued functions. Additional resu...

Approximating fixed points of generalized nonexpansive mappings

Diagonal arguments and fixed points

‎A universal schema for diagonalization was popularized by N.S‎. ‎Yanofsky (2003)‎, ‎based on a pioneering work of F.W‎. ‎Lawvere (1969)‎, ‎in which the existence of a (diagonolized-out and contradictory) object implies the existence of a fixed-point for a certain function‎. ‎It was shown that many self-referential paradoxes and diagonally proved theorems can fit in that schema‎. ‎Here‎, ‎we fi...