Monomialization of a quasianalytic morphism

TL;DR

This paper proves a monomialization theorem for quasianalytic mappings, showing they can be locally transformed into monomials via simple modifications, extending resolution of singularities to a broad class of functions.

Contribution

It establishes a monomialization result for quasianalytic classes, including Denjoy-Carleman and definable smooth functions, using local modifications.

Findings

Monomialization achieved via local blowings-up and power substitutions.

Global blowings-up are insufficient for monomialization in general.

Resolution of singularities concept extended to quasianalytic mappings.

Abstract

We prove a monomialization theorem for mappings in general classes of infinitely differentiable functions that are called quasianalytic. Examples include Denjoy-Carleman classes, the class of $\cC^\infty$ functions definable in a polynomially bounded $o$-minimal structure, as well as the classes of real- or complex analytic functions, and algebraic functions over any field of characteristic zero. The monomialization theorem asserts that a mapping in a quasianalytic class can be transformed to a mapping whose components are monomials with respect to suitable local coordinates, by sequences of simple modifications of the source and target -- local blowings-up and power substitutions in the real cases, in general, and local blowings-up alone in the algebraic or analytic cases. Monomialization is a version of resolution of singularities for a mapping. We show that it is not possible, in general, to monomialize by global blowings-up, even in the real-analytic case.