The Blow-up Analysis on $\mathbf{B}_2^{(1)}$ Affine Toda system: Local mass and Affine Weyl group

TL;DR

This paper extends blow-up analysis of Toda systems to the affine _2^{(1)} system, revealing how local masses relate to the affine Weyl group, and introduces explicit formulas involving two free integers.

Contribution

It provides the first explicit local mass formulas for affine Toda systems, connecting blow-up behavior with the affine Weyl group structure.

Findings

Local mass at blow-up points can be expressed explicitly for _2^{(1)}.

The affine Weyl group influences the transformation of local masses.

Eight types of local mass configurations are identified.

Abstract

It has been established that the local mass of blow-up solutions to Toda systems associated with the simple Lie algebras $\mathbf{A}_n,~\mathbf{B}_n,~\mathbf{C}_n$ and $\mathbf{G}_2$ can be represented by a finite Weyl group. In particular, at each blow-up point, after a sequence of bubbling steps (via scaling) is performed, the transformation of the local mass at each step corresponds to the action of an element in the Weyl group. In this article, we present the results in the same spirit for the affine $\mathbf{B}_2^{(1)}$ Toda system with singularities. Compared with the Toda system with simple Lie algebras, the computation of local masses is more challenging due to the infinite number of elements of the {affine Weyl group of type $\mathbf{B}_{2}^{(1)}$}. In order to give an explicit expression for the local mass formula we introduce two free integers and write down all the possibilities into 8 types. This shows a striking difference to previous results on Toda systems with simple Lie algebras. The main result of this article seems to provide the first major advance in understanding the relation between the blow-up analysis of affine Toda system and the {affine Weyl group} of the associated Lie algebras.