J. Pedraza, A. Russo, A. Svesko, and Z. Weller-Davies. (2022)cite arxiv:2205.05705Comment: 9 pages, 2 figures, Received honorable mention for the 2022 Essay Competition of the Gravity Research Foundation; References added, to appear in the October 2022 Special Issue of the International Journal of Modern Physics D.
M. Tegmark. (1997)cite arxiv:gr-qc/9702052Comment: Minor modifications to match published version. 5 pages. Color figures and related links at http://www.sns.ias.edu/~max/dimensions.html (faster from the US), from http://www.mpa-garching.mpg.de/~max/dimensions.html (faster from Europe) or from max@ias.edu.
T. Jacobson. (1995)cite arxiv:gr-qc/9504004
Comment: 8 pages, 1 figure. Revised version has core unchanged but paper
rewritten and expanded to clarify the reasoning and to emphasize some points.
One figure added.
S. Carlip. (2010)cite arxiv:1009.1136
Comment: 14 pages, two eps figures; to appear in Foundations of Space and
Time, edited by George Ellis, Jeff Murugan, Amanda Weltman (Cambridge
University Press).