Subject: The anticipation region
Date: Thu, 17 Mar 2005 22:35:04 +0200 From: Dimi Chakalov <dimi@chakalov.net> To: Mark Hogarth <mhogarth@cantab.net> CC: Klaus Scharff <klaus.scharff@arcor.de>, Michael L G Redhead <mlr1000@cus.cam.ac.uk>, Nick Bostrom <nick@nickbostrom.com>, Oliver Pooley <oliver.pooley@philosophy.oxford.ac.uk>, Rituparno Goswami <goswami@tifr.res.in>, Pankaj S Joshi <psj@tifr.res.in>, Cenalo Vaz <vaz@physics.uc.edu>, Louis Witten <witten@physics.uc.edu>, Roger Penrose <rouse@maths.ox.ac.uk> Dear Dr. Hogarth, I very much like your idea that the possibility of prediction
http://www.Goddoesnotplaydice.net/Einstein.html#addendum I will appreciate your professional comments, as well as those from your colleagues. Kindest regards, Dimi Chakalov
References [Ref. 1] Mark Hogarth, A Remark Concerning Prediction and Spacetime Singularities, Studies in History and Philosophy of Modern Physics, 28(1), 6371 (March 1997). "Abstract "Intuitively, singularities may be thought to oppose prediction,
but in
"Thirdly, not all singularities cause trouble for determinism:
only
"Now Theorem 1 proves that LP universes are singular, but another result (Corollary 2 in Section 3) actually shows that in any LP spacetime there is a welldefined region ‘between’ the event at which the prediction occurs and the event being predicted which must be nonsingular (nonsingular in a sense made precise in Section 3). I call this the anticipation region (again, made precise in Section 3), socalled because an observer in this region is either anticipating, or can manoeuvre into a position and begin to anticipate, what will happen at the predicted event. See Figure 2. Theorem 1 and Corollary 2 combine to show that in LP universes the complement of the anticipation region must be singular. "This, incidentally, does not imply the existence of unpredictable
"The obvious physical interpretation of Theorem 1 is that
prediction
[Ref. 2] Rituparno Goswami, Pankaj S. Joshi, Cenalo Vaz, and Louis Witten, A TimeLike Naked Singularity, grqc/0410041 v1 "We have an example that shows that even in spherically
symmetric
=============== Subject: How to dispense from world
points
Dear Luca and Massimo, I'm reading your recent paper "General Covariance and the Objectivity of SpaceTime PointEvents" [Ref. 1] with great interest. I believe the general conjecture of Bergmann and Komar [Ref. 2] and your concrete hypothesis about a canonical basis of scalars, which could render "physical individuation of pointevents fully invariant and objective" [Ref. 1], tallies to my efforts to suggest a Global Mode (GM) of spacetime, http://www.Goddoesnotplaydice.net/Einstein.html#addendum Namely, we think of the "points" in the GM as intrinsically
individuated *potential* events, where 'intrinsic' means that their identity
is independent of the metric tensor field and its derivatives  a conjecture
that might be loosely associated with some kind of GM
More on Einstein's GR at http://www.Goddoesnotplaydice.net/Tresser.html#Laszlo_reply http://www.Goddoesnotplaydice.net/Hogarth.html http://www.Goddoesnotplaydice.net/Etera.html#addendum Best regards, Dimi
References [Ref. 1] Luca Lusanna and Massimo Pauri, General Covariance and the Objectivity of SpaceTime PointEvents. Invited Contribution to the ESF 2004 Oxford Conference on SpaceTime. March 17, 2005, grqc/0503069 v1 "From the physicists' point of view, GR has indeed been
immunized
"Let us point out that the explicit expression of the
gauge variables
"The main result of our analysis is given in Section V where we show how the ontic part of the metric (the intrinsic degrees of freedom of the gravitational field) may confer a physical individuation onto spacetime points. Since  as mentioned before  such degrees of freedom depend in a highly nonlocal way upon the values of the metric and its derivatives over a whole spacelike surface of distant simultaneity, pointevents receive a peculiar sort of intrinsic properties that, nevertheless, are conferred on them holistically. "Admittedly, the distinction between ontic and epistemic
parts, as well as the form of the spacelike surfaces of distant simultaneity,
are gaugedependent (noninvariant). Yet, according to a main conjecture
we have advanced in Ref. [14], a canonical basis of scalars should exist,
making the above distinction and, therefore, physical individuation of
pointevents fully invariant and objective."
[Ref. 2] Peter G. Bergmann and Arthur Komar, The Coordinate Group Symmetries of General Relativity, Int. J. Theor.Phys. 5, 1528 (1972). "In general relativity the identity of a world point is
not preserved under the theory's widest invariance group. This assertion
forms the basis for the conjecture that some physical theory of the future
may teach us how to dispense with world points as the ultimate constituents
of spacetime altogether."
