On the geometry of $Diff(S^1)-$pseudodifferential operators based on renormalized traces

TL;DR

This paper explores the geometric structure of a central extension of the diffeomorphism group of the circle involving pseudodifferential operators, introducing a renormalized trace-based metric and analyzing its properties.

Contribution

It introduces a new geometric framework for a central extension of $Diff(S^1)$ using renormalized traces, extending previous metrics and exploring connections.

Findings

Defined a right-invariant pseudo-Riemannian metric using renormalized traces.

Analyzed the relationship with the restricted general linear group $GL_{res}$.

Described classes of notable connections on the group.

Abstract

In this article, we examine the geometry of a group of Fourier-integral operators, which is the central extension of $Diff(S^1)$ with a group of classical pseudo-differential operators of any order. Several subgroups are considered, and the corresponding groups with formal pseudodifferential operators are defined. We investigate the relationship of this group with the restricted general linear group $GL_{res},$ we define a right-invariant pseudo-Riemannian metric on it that extends the Hilbert-Schmidt Riemannian metric by the use of renormalized traces of pseudo-differential operators, and we describe classes of remarkable connections.