Clifford Algebra of Two-Forms, Conformal Structures and Field Equations
  I review the equivalence between duality operators on two-forms and conformal structures in four dimensions, from a Clifford algebra point of view (due to Urbantke and Harnett). I also review an application, which leads to a set of "neighbours" of Einstein's equations. An attempt to formulate reality conditions for the "neighbours" is discussed. 
Ingemar Bengtsson