The trace-free Einstein tensor is not variational for the metric as field variable
Abstract
Abstract It is well-known that the trace-free Einstein tensor of a pseudo-Riemannian metric cannot arise by variation of a local diffeomorphism-invariant action functional with the (inverse) metric as field variable. We show that this statement remains true even for general local actions, without the assumption of diffeomorphism invariance.
Fields of Study & Subjects
Geometric Analysis and Curvature Flows
Advanced Differential Geometry Research
Cosmology and Gravitation Theories
Publication details
- Journal / source
- Classical and Quantum Gravity
- Publisher
- IOP Publishing
- Volume
- 43
- Issue
- 4
- Pages
- 047001–047001
- Publication date
- 17 February 2026
- Language
- EN