The Causal Event Set
  To clarify some aspects of the application of Special Relativity, spacetime is sliced into null geodesic hypersurfaces as an alternative to the hypersurfaces of simultaneity normally adopted. Events at particle locations on the hypersurface are identified as the causal event set. It is demonstrated that a Lorentz boost applied to the causal event set maintains the property of connectedness and with this formalism it is simple to derive the redshift equation. The twin paradox is naturally explained as an instantaneous reconfiguration of particle position 4-vectors in the frame of the accelerated object. The metaphysical implications are examined with the tentative conclusion that a relationist view of spacetime is more consistent with this treatment than the substantivalist viewpoint. 
Alasdair Macleod