ABSTRACT The equivalence problem in general relativity arises from the arbitrariness of coordinat... more ABSTRACT The equivalence problem in general relativity arises from the arbitrariness of coordinate choice and is the problem of deciding whether two apparently, different space-times are (locally) identical or not. Here we review the basic procedure for resolving this question, and its practical implementation, as presented in previous papers, and report on recent theoretical and practical research in this area. Some of the techniques are of interest in other problems; in particular, they may be applicable to tests of the equivalence of systems of differential equations.
ABSTRACT Part I. Foundations: 1. The nature of cosmology; 2. Geometry; 3. Classical physics and g... more ABSTRACT Part I. Foundations: 1. The nature of cosmology; 2. Geometry; 3. Classical physics and gravity; Part II. Relativistic Cosmological Models: 4. Kinematics of cosmological models; 5. Matter in the Universe; 6. Dynamics of cosmological models; 7. Observations in cosmological models; 8. Light-cone approach to relativistic cosmology; Part III. The Standard Model and Extensions: 9. Homogeneous FLRW universes; 10. Perturbations of FLRW universes; 11. The cosmic background radiation; 12. Structure formation and gravitational lensing; 13. Confronting the Standard Model with observations; 14. Acceleration from dark energy or modified gravity; 15. 'Acceleration' from large scale inhomogeneity?; 16. 'Acceleration' from small scale inhomogeneity?; Part IV. Anisotropic and Inhomogeneous Models: 17. The space of cosmological models; 18. Spatially homogeneous anisotropic models; 19. Inhomogeneous models; Part V. Broader Perspective: 20. Quantum gravity and the start of the Universe; 21. Cosmology in a larger setting; 22. Conclusion: our picture of the Universe; Appendix; References; Index.
This book is a self-contained introduction to key topics in ad-vanced general relativity. The ope... more This book is a self-contained introduction to key topics in ad-vanced general relativity. The opening chapter reviews the subject, with strong emphasis on the geometric structures un-derlying the theory. The second chapter discusses 2-component spinor theory, its usefulness for ...
We review the matching conditions for a collapsing anisotropic cylindrical perfect fluid, recentl... more We review the matching conditions for a collapsing anisotropic cylindrical perfect fluid, recently discussed in the literature (2005 {\it Class. Quantum Grav.} {\bf 22} 2407). It is shown that radial pressure vanishes on the surface of the cylinder, contrary to what is asserted in that reference. The origin of this discrepancy is to be found in a mistake made in one step of the calculations. Some comments about the relevance of this result in relation to the momentum of Einstein--Rosen waves are presented.
... [14] MAH MacCallum and JEF Skea, SHEEP: A computer algebra system for general relativity, in:... more ... [14] MAH MacCallum and JEF Skea, SHEEP: A computer algebra system for general relativity, in: MJ Reboucas and WL Roque, eds., Algebraic Computing in General Relativity, Lecture Notes from the First Brazilian School on Computer Algebra, Vol. IT (Oxford Univ. ...
ABSTRACT The equivalence problem in general relativity arises from the arbitrariness of coordinat... more ABSTRACT The equivalence problem in general relativity arises from the arbitrariness of coordinate choice and is the problem of deciding whether two apparently, different space-times are (locally) identical or not. Here we review the basic procedure for resolving this question, and its practical implementation, as presented in previous papers, and report on recent theoretical and practical research in this area. Some of the techniques are of interest in other problems; in particular, they may be applicable to tests of the equivalence of systems of differential equations.
ABSTRACT Part I. Foundations: 1. The nature of cosmology; 2. Geometry; 3. Classical physics and g... more ABSTRACT Part I. Foundations: 1. The nature of cosmology; 2. Geometry; 3. Classical physics and gravity; Part II. Relativistic Cosmological Models: 4. Kinematics of cosmological models; 5. Matter in the Universe; 6. Dynamics of cosmological models; 7. Observations in cosmological models; 8. Light-cone approach to relativistic cosmology; Part III. The Standard Model and Extensions: 9. Homogeneous FLRW universes; 10. Perturbations of FLRW universes; 11. The cosmic background radiation; 12. Structure formation and gravitational lensing; 13. Confronting the Standard Model with observations; 14. Acceleration from dark energy or modified gravity; 15. 'Acceleration' from large scale inhomogeneity?; 16. 'Acceleration' from small scale inhomogeneity?; Part IV. Anisotropic and Inhomogeneous Models: 17. The space of cosmological models; 18. Spatially homogeneous anisotropic models; 19. Inhomogeneous models; Part V. Broader Perspective: 20. Quantum gravity and the start of the Universe; 21. Cosmology in a larger setting; 22. Conclusion: our picture of the Universe; Appendix; References; Index.
This book is a self-contained introduction to key topics in ad-vanced general relativity. The ope... more This book is a self-contained introduction to key topics in ad-vanced general relativity. The opening chapter reviews the subject, with strong emphasis on the geometric structures un-derlying the theory. The second chapter discusses 2-component spinor theory, its usefulness for ...
We review the matching conditions for a collapsing anisotropic cylindrical perfect fluid, recentl... more We review the matching conditions for a collapsing anisotropic cylindrical perfect fluid, recently discussed in the literature (2005 {\it Class. Quantum Grav.} {\bf 22} 2407). It is shown that radial pressure vanishes on the surface of the cylinder, contrary to what is asserted in that reference. The origin of this discrepancy is to be found in a mistake made in one step of the calculations. Some comments about the relevance of this result in relation to the momentum of Einstein--Rosen waves are presented.
... [14] MAH MacCallum and JEF Skea, SHEEP: A computer algebra system for general relativity, in:... more ... [14] MAH MacCallum and JEF Skea, SHEEP: A computer algebra system for general relativity, in: MJ Reboucas and WL Roque, eds., Algebraic Computing in General Relativity, Lecture Notes from the First Brazilian School on Computer Algebra, Vol. IT (Oxford Univ. ...
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Papers by Malcolm Maccallum