The zero-curvature representation for the $O(2,1)$ sigma-model

A. G. Bytsko

St. Petersburg Department of Steklov Mathematical Institute of Russian Academy of Sciences

Abstract: It is shown that for the $O(2,1)$ sigma-model, there is a zero-curvature representation which admits an ultralocal fundamental Poisson bracket.

Key words and phrases: non-compact sigma-model, zero-curvature representation, fundamental Poisson bracket.

UDC: 517, 539.1.01

Received: 29.10.2025