context: It is impossible that Julius is yellow. It is likely that Bernhard is green. Chances are about even that John dropped the milk.
hypothesis: We believe that 'John dropped the milk and Bernhard is green'.
valid_hypothesis: It is probably not the case that 'John dropped the milk and Bernhard is green'.
invalid_hypothesis: We believe that 'John dropped the milk and Bernhard is green'.
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
    0.0::factA.
    0.7::factB.
    0.5::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'John dropped the milk and Bernhard is green'.