  This note represents a stepping stone from the discovery of the precise
mathematical formula for electromagnetic field generated by a moving point
charge, the amended Feynman formula, see Bogdan arXiv:0909.5240, and leading to
the to the general formula of gravitational and electromagnetic fields
generated by moving matter in a Lorentzian frame of special theory of
relativity, Bogdan arXiv:0910.0538.
  In this note the author introduces the notion of flow of matter in a
Lorentzian frame. This notion is relativistic in the sense of Einstein's
special theory of relativity.
  The author presents explicit formulas suitable for a digital computer
permitting one to find time delay for an action from a flow line to any point
in the Lorentzian frame. The time delay field for any flow of plasma in a fixed
Lorentzian frame is unique.
  Using this field he introduces the retarded time field and fundamental fields
corresponding to the flow with a free parameter representing the initial
positions of the lines of flow.
  By means of these fields one can represent and establish relations between
wave, Lorentz gauge, and Maxwell equations, and Lienard-Wiechert potentials,
and amended Feynman's formula.
  The initial distribution of charges over the initial position of the flow is
given by a signed measure of finite variation defined over Borel sets. It may
include discrete and continuous components.
