A Dynamical Framework for the McKay Correspondence via Gauge-Theoretic Morse Flow
Jiajun Yan
TL;DR
This work introduces a gauge-theoretic Morse-flow framework to realize the McKay correspondence dynamically on Kronheimer's ALE spaces, recasting the static basis–representation bijection as a flow-based identification between $H^2(X)$ generators and irreducible representations of the finite subgroup $oldsymbol{\Gamma} o SU(2)$. By constructing an $S^1$-invariant Morse-Bott function on the ALE moduli space and analyzing gradient trajectories of flat connections, the authors associate 1-parameter holonomy representations to flow lines and show convergence to irreducible representations at infinity; they prove the mechanism for cyclic groups $oldsymbol{\Gamma} o Z_n$ in the paper and provide detailed verifications for $oldsymbol{\Gamma}=Z_2$ and $Z_3$. The approach unifies Kronheimer’s gauge-theoretic ALE construction with Morse theory, offering a dynamic interpretation of the McKay correspondence and highlighting a bridge to potential connections with Floer-theoretic and symplectic viewpoints. These results suggest a broader framework in which cohomology generators are recovered as asymptotic projectors along gradient flows, with explicit computations validating the conjecture in key low-rank cyclic cases.
Abstract
The McKay correspondence establishes a bijection between the cohomology of a minimal resolution and the irreducible representations of a finite subgroup $Γ\subset \text{SU}(2)$. While traditional proofs rely on static algebraic isomorphisms, we propose a dynamical framework grounded in gauge theory and Morse-Bott theory. We analyze an $S^1$-invariant Morse-Bott function on the minimal resolution, interpreting its gradient flow lines as $1$-parameter families of holonomy representations of flat connections from $Γ$ to $GL(R)$. We conjecture that the flow emanating from a critical submanifold converges asymptotically at the boundary to a specific irreducible representation of $Γ$. This dynamical process explicitly constructs the identification between the cohomology basis and the irreducible representations of $Γ$ prescribed by the McKay correspondence. We prove this conjecture for cyclic cases.
