-- Basic idea: infinite resitance, conductive exist.  Is there a way
-- to represent conductivity/resistance as a projective entity?
-- Primal/dual, projective?

--   conductive: G I = V
--   resistivie: R V = I
--   projective: A I + B V = 0  (or A [I,V] = 0 ?)
--
--  If either G or R is not full rank, the inverse "view" is not
--  correct.  Questions: does it really matter?  Infinities arise only
--  when infinite resitance, conductance appears.