Talk:Causal sets

From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Physics (Rated C-class, Mid-importance)
WikiProject icon This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
C-Class article C  This article has been rated as C-Class on the project's quality scale.
 Mid  This article has been rated as Mid-importance on the project's importance scale.
 

Geodesics[edit]

Shouldn't the definition of geodesic, currently "The length of the chain, n, is maximal over all chains from x\, to y\,." be "minimal" instead?

It depends on the signature you adopt for Minkowski Space - if [1, -1, -1, -1] then maximal corresponds to not swanning about in space. The causal property prevents you swanning about in time.

75.67.249.169 (talk) 23:40, 23 October 2012 (UTC)

We're not talking about the length in Minkowski space, n is simply the number of links in the chain. What does the metric have to do with it? — Preceding unsigned comment added by 130.216.209.138 (talk) 03:01, 28 June 2013 (UTC)

Relevant?[edit]

Russell and Whitehead's theory of space-time, called "eventism," reduces to the theory of causal sets when it is constrained to finite sets of events. Causal sets form relative frequencies, which leads directly to the definition of mass-energy in accord with Planck's E=hf. Each "causal link" is then a quantum. Fundamental particles, including the electron, neutrino, proton and neutron, have been modeled by Carey R. Carlson as simple causal sets.

This paragraph was moved from the main causal set article because it is unclear (e.g. "Each causal link is then a quantum"??), unsourced (e.g Where's a reference for Russell and Whitehead's eventism theory? Carey R. Carlson's work?) and contains incorrect statements (e.g. the proton and neutron are not fundamental particles - see quarks). StevenJohnston (talk) 13:46, 22 February 2008 (UTC)

To clarify, there are no fundamental particles at all when physics is reduced to causal sets. There are only the elements (relata) and the pairing relations (causal links.) This reduced ontology is sufficient to construct the nuclei and the electron clouds of the atoms as causal sets, as well as the neutrino modes of propagation. I self-published my initial findings as "A Theory of Everything for Physics" in 2005, without having heard about "causal sets." I have an article coming out soon in a collection edited by David Skrbina, which will subject my work to its first peer review. David's book is "Mind That Abides: Panpsychism in the New Millenium." My article is "Finite Eventism." Search the phrase "finite eventism" for links to David's book and my posted writings, including "The Structure of Quarks." 71.37.249.99 (talk) 16:51, 3 November 2008 (UTC)

I've posted the theory and its diagrams on a site called "viXra." Here is a link to the paper, and a copy of its abstract: http://vixra.org/abs/1006.0070 "Causal Set Theory and the Origin of Mass-ratio" Quantum theory is reconstructed using standalone causal sets. The frequency ratios inherent in causal sets are used to define energy-ratios, implicating the causal link as the quantum of action. Space-time and its particle-like sequences are then constructed from causal links. A 4-D time-lattice pattern is defined and used to model neutrinos and electron clouds, which together constitute our 4-D manifold. A 6-D time-lattice is used to model the nucleons. The integration of the nucleus with its electron cloud allows calculation of the mass-ratio of the proton (or the neutron) with respect to the electron. Arrow diagrams, along with several ball-and-stick models, are used to streamline the presentation. -- Carey 71.210.164.16 (talk) 18:57, 6 July 2010 (UTC)

Partial orders are REFLEXIVE (not irreflexive)[edit]

On http://www.phy.olemiss.edu/~luca/Topics/c/causal_sets.html you find the following definition:

Causal set: A (locally) finite partially ordered set, in which the order is causally interpreted.

See also the nlab entry http://ncatlab.org/nlab/show/causet. HansBlatter (talk) 11:39, 21 October 2009 (UTC)


They can be either reflexive or irreflexive, it does not matter. Each convention is more convenient in different contexts. Though if you discard irreflexivity you must impose acyclicity. 129.97.120.253 (talk) 14:54, 8 November 2010 (UTC)

Length of Chains[edit]

There is a problem with the definition of length of chains. x0<x1 is length 1, if it is correct that the length is the number of relations in the chain, but according to the given enumeration (x0 ...x(n-1)) and the statement that the length is the value of n, we get a length of 2.!

75.67.249.169 (talk) 12:30, 23 October 2012 (UTC)

No, the definition is consistent, in your example (that is, x0<x1) n is 1.Paolo Lipparini (talk) 10:15, 10 September 2014 (UTC)