Comment on "Failure of standard conservation laws at a classical change of signature"

Abstract

Hellaby & Dray (gr-qc/9404001) have recently claimed that matter conservation fails under a change of signature, compounding earlier claims that the standard junction conditions for signature change are unnecessary. In fact, if the field equations are satisfied, then the junction conditions and the conservation equations are satisfied. The failure is rather that the authors did not make sense of the field equations and conservation equations, which are singular at a change of signature.

3 pages, TeX

References in corpus (8)

• The Origin of Time Asymmetry
• The Scalar Field Equation in the Presence of Signature Change
• Failure of Standard Conservation Laws at a Classical Change of Signature
• Hamiltonian quantization of General Relativity with the change of signature
• On Cosmological Isotropy, Quantum Cosmology and the Weyl Curvature Hypothesis
• Junction Conditions for Signature Change
• Real Tunneling Solutions and the Hartle-Hawking Wave Function
• Scalar and Spinor Fields in Signature Changing Spacetimes

Cited by in corpus (19)

• Avoiding singularities in Lorentzian-Euclidean black holes: the role of atemporality
• Wave packets and initial conditions in quantum cosmology
• Signature change events: A challenge for quantum gravity?
• On Singular Semi-Riemannian Manifolds
• Reply Comment: Comparison of Approaches to Classical Signature Change
• On signature transition in Robertson-Walker cosmologies
• Variational equations on mixed Riemannian-Lorentzian metrics
• Note on Signature Change and Colombeau Theory
• Singular General Relativity
• Isochronous Spacetimes
• Signature Change at Material Layers and Step Potentials
• Casimir effect in a two dimensional signature changing spacetime
• Casimir stress on parallel plates in de Sitter space with signature change
• Casimir effect for a spherical shell in de Sitter spacetime with signature change
• Distinguished solutions for discontinuous signature change with weak junction conditions
• Diffeomorphism algebra of two dimensional free massless scalar field with signature change
• Isochronous solutions of Einstein's equations and their Newtonian limit
• Geodesic family of spherical instantons and cosmic quantum creation
• Casimir effect for concentric spheres in de Sitter spacetime with signature change