Remarks on the exotic central extension of the planar Galilei group

TL;DR

This paper discusses the relationship between the exotic central extension of the planar Galilei group and parameters in the relativistic theory, clarifying conceptual issues in the non-relativistic limit.

Contribution

It provides insights into how the exotic central extension relates to relativistic parameters, addressing ambiguities in the non-relativistic limit of the Galilei group.

Findings

Clarifies the connection between the exotic extension and relativistic parameters

Addresses issues in relating non-relativistic and relativistic theories

Provides conceptual understanding of the central extension in planar Galilei group

Abstract

Some issues in relating the central extensions of the planar Galilei group to parameters in the corresponding relativistic theory are discussed.