An inverse function theorem for free groups

Implicit function theorem over free groups

We introduce the notion of a regular quadratic equation and a regular NTQ system over a free group. We prove the results that can be described as Implicit function theorems for algebraic varieties corresponding to regular quadratic and NTQ systems. We will also show that the Implicit function theorem is true only for these varieties. In algebraic geometry such results would be described as lift...

An inverse function theorem in Fréchet spaces

I present an inverse function theorem for differentiable maps between Fréchet spaces which contains the classical theorem of Nash and Moser as a particular case. In contrast to the latter, the proof does not rely on the Newton iteration procedure, but on Lebesgue’s dominated convergence theorem and Ekeland’s variational principle. As a consequence, the assumptions are substantially weakened: th...

An Inverse Function Theorem for Metrically Regular Mappings

We prove that if a mapping F : X → → Y , where X and Y are Banach spaces, is metrically regular at x̄ for ȳ and its inverse F−1 is convex and closed valued locally around (x̄, ȳ), then for any function G : X → Y with lipG(x̄) · regF (x̄ | ȳ)) < 1, the mapping (F + G)−1 has a continuous local selection x(·) around (x̄, ȳ + G(x̄)) which is also calm.

On the Inverse Function Theorem

Theorem for an Inverse Problem

Let VZu+k2u+k2a~(z)u+V.(a~(~)Vu) = -6(cc-y) inR3, where al(z) EL’(D), a&) E H’(D), D E R3_ = {z : 13 < 0) is a finite region, aj(Z) = 0 outside of D, j = 1,2, 1 + 02 > 0, al = El. Assume that thedatau(l,y,k),V~,yEP={I:13=0}8ndallkE(O,ko),ko>O is an arbitrary small number, are given. THEOREM. The above data determine aj(z), j = 1,2, uniquely.