A simple criterion for nonrotating reference frames

TL;DR

This paper presents a straightforward criterion to determine when a reference frame with fixed spacelike coordinates is nonrotating according to Walker's definition, supported by theoretical proof and applications.

Contribution

It introduces a simple, verifiable condition for nonrotation of reference frames, enhancing understanding and practical assessment in relativity.

Findings

Provides a necessary and sufficient condition for nonrotation.

Offers a practical criterion that can be easily checked.

Includes applications demonstrating the criterion's usefulness.

Abstract

We prove a theorem that gives an easily verifiable necessary and sufficient condition for a reference frame with fixed spacelike coordinates to be nonrotating in the sense of Walker. Applications are discussed.