A sequential implicit function theorem for iterative solution of generalized equation involving point-based approximation

In this paper we study the local convergence of the method

$$0\in A(p,x_{k},x_{k+1})+F(x_{k+1}).$$     

An implicit function theorem

Suppose thatF:DR ⁿ×R^mRⁿ, withF(x ⁰,y ⁰)=0. The classical implicit function theorem requires thatF is differentiable with respect tox and moreover that ₁ F(x ⁰,y ⁰) is nonsingular. We strengthen this theorem by removing the nonsingularity and differentiability requirements and by replacing them with a one-to-one condition onF as a function ofx.     

A note on the implicit function theorem for quasi-linear eigenvalue problems

We consider the quasi-linear eigenvalue problem −Δ_pu=λg(u) subject to Dirichlet boundary conditions on a bounded open set Ω, where g is a locally Lipschitz continuous function. Imposing no further conditions on Ω or g, we show that for λ near zero the problem has a bounded solution which is unique in the class of all small solutions. Moreover, this curve of solutions parameterized by λ depends continuously on the parameter.     

An implicit function theorem for directionally differentiable functions

A new implicit function theorem for a class of nonsmooth functions is proved. It is used to improve the directional implicit function theorem of Demidova and Demyanov (Ref. 1).     

An implicit function theorem for algebraically closed fields

Let F be an algebraically closed field of characteristic 0, and let f : F ⁿ → F. We show that f is implicitly definable by a system of polynomial equations if and only if f is a special kind of piecewise rational function.     

An implicit function theorem: Comment

In Ref. 1, Jittorntrum proposed an implicit function theorem for a continuous mappingF:R ⁿ ×R ^m R ⁿ, withF(x ⁰,y ⁰)=0, that requires neither differentiability ofF nor nonsingularity of _x F(x ⁰,y ⁰). In the proof, the local one-to-one condition forF(·,y):A R ⁿ R ⁿ for ally B is consciously or unconsciously treated as implying thatF(·,y) mapsA one-to-one ontoF(A, y) for ally B, and the proof is not perfect. A proof can be given directly, and the theorem is shown to be the strongest, in the sense that the condition is truly if and only if.     

Smooth bifurcation for variational inequalities based on the implicit function theorem

We present a certain analog for variational inequalities of the classical result on bifurcation from simple eigenvalues of Crandall and Rabinowitz. In other words, we describe the existence and local uniqueness of smooth families of nontrivial solutions to variational inequalities, bifurcating from a trivial solution family at certain points which could be called simple eigenvalues of the homogenized variational inequality. If the bifurcation parameter is one-dimensional, the main difference between the case of equations and the case of variational inequalities (when the cone is not a linear subspace) is the following: For equations two smooth half-branches bifurcate, for inequalities only one. The proofs are based on scaling techniques and on the implicit function theorem. The abstract results are applied to a fourth order ODE with pointwise unilateral conditions (an obstacle problem for a beam with the compression force as the bifurcation parameter).     

An implicit function theorem for Banach spaces and some applications

We prove a generalized implicit function theorem for Banach spaces, without the usual assumption that the subspaces involved being complemented. Then we apply it to the problem of parametrization of fibers of differentiable maps, the Lie subgroup problem for Banach–Lie groups, as well as Weil’s local rigidity for homomorphisms from finitely generated groups to Banach–Lie groups.      

The implicit function theorem in a non-Archimedean setting

In this paper, the inverse function theorem and the implicit function theorem in a non-Archimedean setting will be discussed. We denote by N any non-Archimedean field extension of the real numbers that is real closed and Cauchy complete in the topology induced by the order; and we study the properties of locally uniformly differentiable functions from Nⁿ to N^m. Then we use that concept of local uniform differentiability to formulate and prove the inverse function theorem for functions from Nⁿ to Nⁿ and the implicit function theorem for functions from Nⁿ to N^m with m<n.     

Properties of countable separation and implicit function theorem

We consider some properties of countable separation for familiesA andD of subsets of a setX by means of elements of a fixed familyM⊂P(X). We give necessary and sufficient conditions, in terms of measurability of some sets constructed by means of multifunctions, in order that the familiesA andD satisfy such a property. As an application we derive an implicit function theorem for functions ofCarathéodory-type. Supported by 60% and 40% research fund of M.P.I. of Italy.     

Parallel iteration schemes for implicit ODEIVP methods

In this contribution to the Proceedings of the “International Symposium on New Aspects of Numerical Analysis in the Light of Recent Technology” held at Stresa on 13 until 18 September 1993, we give a survey of recent research at CWI for solving the implicit relations arising in ODEIVP methods on parallel computers. Starting with a General Linear method as introduced by Butcher, three forms of parallelism for solving the associated implicit equations are discussed, viz. (i) parallelism across the stages within a single step (stage parallelism), (ii) parallel preconditioners, and (iii) parallelism across the steps (step parallelism). The structure of these type of parallel methods will be described.     

Global solution branches and a topological implicit function theorem

We show some abstract (purely set-topological) principles which allow to prove the existence of global solution branches. The results apply either for the locally compact situation and then allow to prove global bifurcation results of Rabinowitz type, or they apply for a locally connected situation and allow to prove global branches of arbitrarily small perturbations without any compactness hypotheses. As two applications, we obtain a generalization of the Rabinowitz theorem for bifurcation from an interval and an implicit function type theorem for nondifferentiable functions.     

Busy periods of discrete-time queues using the Lagrange implicit function theorem

In this paper, we study the busy-period distribution for discrete-time queues assuming a Bernoulli arrival process, with arbitrary service-time and batch-arrival distributions. We derive explicit analytic formulas for these distributions using the Lagrange Implicit Function Theorem applied to probability generating functions. The convenient coefficient operator notation used in these formulas leads to a computationally efficient method for obtaining the distributions in their entirety from these analytic formulas.     

Applications of the ergodic iteration theorem

I prove several natural preservation theorems for the countable support iteration. This solves a question of Ros?anowski regarding the preservation of localization properties and greatly simplifies the proofs in the area (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)