An Order of Magnitude Calculus
  This paper develops a simple calculus for order of magnitude reasoning. A
semantics is given with soundness and completeness results. Order of magnitude
probability functions are easily defined and turn out to be equivalent to kappa
functions, which are slight generalizations of Spohn's Natural Conditional
Functions. The calculus also gives rise to an order of magnitude decision
theory, which can be used to justify an amended version of Pearl's decision
theory for kappa functions, although the latter is weaker and less expressive.
