Uniform Oscillatory Integral estimates for Convex Phases via Sublevel Set estimates

TL;DR

This paper explores the relationship between oscillatory integral estimates and sublevel set estimates for convex functions, establishing precise control under new geometric assumptions beyond finite type conditions.

Contribution

It introduces an alternative geometric assumption that ensures precise control of oscillatory integrals for convex phases without finite type restrictions.

Findings

Established precise control under new geometric assumptions

Extended previous results beyond finite type conditions

Clarified when oscillatory integral estimates imply sublevel set estimates

Abstract

We examine the relation between oscillatory integral estimates and sublevel set estimates associated to convex functions. Whilst the former implies the latter in many cases, the reverse requires additional assumptions. Under finite (line) type assumptions, Bruna, Nagel & Wainger were able to demonstrate a very precise control of oscillatory integrals with convex phases via their sublevel sets. Without the finite type assumption, certain erratic behaviour can force this precise control to fail (Bak, McMichael, Vance & Wainger). We establish the same precise control under an alternative qualitative geometric assumption.