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Main Author: Petroulakis, George
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.05369
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author Petroulakis, George
author_facet Petroulakis, George
contents This article introduces a framework for the localization and isolation of singularities in the affine Grassmannian. Our primary result is a structural factorization of the transition matrix $C$ between the Mirković--Vilonen (MV) basis and the convolution basis into $C = P \cdot M \cdot A \cdot Q^{-1}$, where the four factors represent: equivariant localization ($Q$), fusion via nearby cycles ($A$), local intersection cohomology stalks ($M$), and diagonal normalization ($P$). Utilizing this factorization, and by introducing the Geometric Efficiency metric ($η$) we establish a Universal Geometric Rank Bound, proving that the rank of the transition matrix $C$ is bounded by the dimension of the local Braden--MacPherson (BMP) stalks.
format Preprint
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institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Localization of Singularities and Universal Geometric Rank Bounds in the Satake Correspondence
Petroulakis, George
Algebraic Geometry
Representation Theory
This article introduces a framework for the localization and isolation of singularities in the affine Grassmannian. Our primary result is a structural factorization of the transition matrix $C$ between the Mirković--Vilonen (MV) basis and the convolution basis into $C = P \cdot M \cdot A \cdot Q^{-1}$, where the four factors represent: equivariant localization ($Q$), fusion via nearby cycles ($A$), local intersection cohomology stalks ($M$), and diagonal normalization ($P$). Utilizing this factorization, and by introducing the Geometric Efficiency metric ($η$) we establish a Universal Geometric Rank Bound, proving that the rank of the transition matrix $C$ is bounded by the dimension of the local Braden--MacPherson (BMP) stalks.
title Localization of Singularities and Universal Geometric Rank Bounds in the Satake Correspondence
topic Algebraic Geometry
Representation Theory
url https://arxiv.org/abs/2601.05369