context: Chances are about even that Bernhard is a rhino. There is almost no chance that John went to the office. We believe that Jeff discarded the milk.
hypothesis: We believe that 'Jeff discarded the milk' or 'John went to the office' or both.
valid_hypothesis: We believe that 'Jeff discarded the milk' or 'John went to the office' or both.
invalid_hypothesis: It is unlikely that 'Jeff discarded the milk' or 'John went to the office' or both.
problog: 
    and(A,B) :- A,B.
    or(A,B) :- A;B.
    nand(A,B) :- not(and(A,B)).
    nor(A,B) :- not(or(A,B)).
    xor(A,B) :- or(A,B), nand(A,B).
  
    %hop0
    0.5::factA.
    0.02::factB.
    0.75::factC.
    
  
    %hop2
    conclusion:-or(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Jeff discarded the milk' or 'John went to the office' or both.