[W/K] :: inference rule

  inference rule
       
          A procedure which combines known facts to produce ("infer")
          new facts.  For example, given that
       
          	1. Socrates is a man and that
          	2. all men are motal,
       
          we can infer that Socrates is mortal.  This uses the rule
          known as "modus ponens" which can be written in Boolean
          algebra as
       
          	(A & A => B) => B
       
          (if proposition A is true, and A implies B, then B is true).
       
          Or given that,
       
          	1. Either Denis is programming or Denis is sad and
          	2. Denis is not sad,
       
          we can infer that Denis is programming.  This rule can be
          written
       
          	((A OR B) & not B) => A
       
          (If either A is true or B is true (or both), and B is false,
          then A must be true).
       
          (1994-10-31)