AdS spacetimes and isometric embeddings

An algebraic global isometric embedding of the nonrotating BTZ black hole is presented. The ambient spacetime is $\mathbb{M}^{2,3}$, the 3+2 dimensional flat spacetime. We also present the analogous embedding for the Euclidean BTZ spacetime and by performing a kind of double analytic continuation construct a 1-parameter family of embeddings of cosmological AdS spacetime into $\mathbb{M}^{2,3}$ which coincide asymptotically with the embedded BTZ manifold of the appropriate mass. Finally we note that the family of embeddings of cosmological AdS$_{n}$ into $\mathbb{M}^{2,n}$ generalises to higher dimensions.Comment: To appear in the proceedings of the conference: "Relativity and Gravitation, 100 Years after Einstein in Prague." We give a brief review of the results obtained in [arXiv:1011.3883[gr-qc]]. Lemma 2.2, is a new resul

Inaugural Session, Institute of English Studies Seminar in the History of Libraries

Text of the inaugural session of the Institute of English Studies seminar in the History of Libraries held on 27/2/08

The BTZ spacetime as an algebraic embedding

A simple algebraic global isometric embedding is presented for the nonrotating BTZ black hole and its counterpart of Euclidean signature. The image of the embedding, in Minkowski space of two extra dimensions, is the interection of two quadric hypersurfaces. Furthermore an embedding into $AdS_4$ or $H_4$ is also obtained, showing that the spacetime is of embedding class one with respect to maximally symmetric space of negative curvature. The rotating solution of Euclidean signature is also shown to admit a quadratic algebraic embedding, but seemingly requires more than two extra dimensions.Comment: 15 pages, no figures. version 2: references and acknowledgements added, typos fixed, a paragraph on alternative global coordinates adde

SPARKPLUS for Self- and Peer Assessment on Group-Based Honours’ Research Projects

This paper explores an application of an online tool SPARKPLUS (Self and Peer Assessment Resource Kit) for the self and peer assessment on the group-based Honours’ research projects. The Honours’ research projects in School of Civil, Environmental Engineering at University of Adelaide are running in a small group of students (typically four students or less) working with an academic supervisor in a selected area for one year. Since the research project is self-directed study, it is very difficult to fairly assess the contribution of individual students to the group-based research project. The paper-based method of self and peer assessment for the Honour’s research projects was used in the previous years. The same mark was often distributed and no feedback was given. Both the students and academic staff were not satisfied with the paper-based method of self and peer assessment. Thus an online tool SPARK PLUS together with a set of assessment criteria was used for the self and peer assessment of the Honours’ research projects in 2010. Thirty-seven groups participated in the self and peer assessment of using SPARK PLUS in semester one 2010 and a series of results from the online self and peer assessment were obtained and analysed. Feedback sessions were held and substantial feedback was received from students. Based on the feedback, suggestions were made on improving use of the online tool for self and peer assessment on the Honours’ research project.Chengqing Wu, Emmanuel Chanda and John Willisonhttp://www.adelaide.edu.au/erg