You have probably noticed that the full force of Poincaré's relativity principle isn't necessary to derive the Lorentz transformation and the essence of special relativity: http://www.everythingimportant.org/relativity/ http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000043000005000434000001 [Broken] http://arxiv.org/PS_cache/physics/pdf/0302/0302045.pdf [Broken] You are also very likely aware of the well-known fact that spatially compact spacetimes break global Lorentz invariance and define absolute inertial frames of reference: http://groups.google.com/group/sci.physics.research/msg/e19ac8581a6148f2 Since SR is easily generalized so as to include this interesting class of spacetimes, it's reasonable, then, to amend the relativity principle also. I propose that it be reduced to a tautology. Proposition: All physical laws can be divided into two categories. The two great divisions are the laws that are true in all inertial frames of reference and those that aren't. There are many conjectures, proposed experiments and searches for possible violations of Lorentz invariance. What are the possibilities? Is there a catalogue of current conjectures? Let me list a few ideas and concepts based on possible laws from the second category. 1. Superluminality (a popular favorite) 2. Perfect matter-antimatter symmetry 3. Object length dependence on frame of reference I'm especially interested in the observed asymmetry between kaons and antikaons and whether or not their asymmetric decay is a consequence of a preferred frame. Has a test for this possibility been seriously considered?