2008/09/02 by Michael Greenblatt, Greenblatt, Michael · 2 citations
Computer Science · Mathematics · #42B99 #Advanced Mathematical Modeling in Engineering #Classical Analysis and ODEs (math.CA) #FOS: Mathematics #Spectral Theory in Mathematical Physics #advanced mathematical theories
paper · pdf · doi:10.48550/arxiv.0809.0483
openalex publication_date 2008/09/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A theorem of Varchenko gives the order of decay of the leading term of the asymptotic expansion of a degenerate oscillatory integral with real-analytic phase in two dimensions. His theorem expresses this order of decay in a simple geometric way in terms of its Newton polygon once one is in certain coordinate systems called adapted coordinate systems. In this paper, we give explicit formulas that not only provide the order of decay of the leading term, but also the coefficient of this term. There are three rather different formulas corresponding to three different types of Newton polygon. Analogous results for sublevel integrals are proven, as are analogues for the more general case of smooth phase. The formulas require one to be in certain "superadapted" coordinates. These are a type of adapted coordinate system which we show exists for any smooth phase.