Symbolic Computations of the Two-Colored Diagrams for Central Configurations of the Planar N-vortex Problem
Xiang Yu, Shuqiang Zhu
TL;DR
The paper develops a symbolic-computation framework to enumerate two-colored diagrams arising in the singular-sequence approach to the planar $N$-vortex finiteness problem. By formulating the central-configuration equations as a complex, polynomial extended system and introducing $zw$-matrices, the authors translate diagrammatic rules into matrix constraints and outline an algorithm to exhaustively identify admissible diagrams. They perform a detailed $N=5$ case, obtaining 22 viable diagrams from 31 candidates and excluding 9 diagrams as impossible, illustrating the method’s feasibility and its potential to scale to larger $N$. The work advances finiteness results for vortex relative equilibria and collapse configurations by providing a practical, symbolic route to classify non-finite configurations via two-colored diagrams, building on and adapting prior N-body techniques. The approach has implications for rigorous finiteness proofs and could guide future investigations into higher-vortex systems.
Abstract
We apply the singular sequence method to investigate the finiteness problem for stationary configurations of the planar N-vortex problem. The initial step of the singular sequence method involves identifying all two-colored diagrams. These diagrams represent potential scenarios where finiteness may fail. We develop a symbolic computation algorithm to determine all two-colored diagrams for central configurations of the planar N-vortex problem.
