context: There is almost no chance that John dropped the milk. We doubt that Lily is gray. There is almost no chance that Julius is a frog.
hypothesis: It is impossible that 'John dropped the milk and Julius is a frog'.
valid_hypothesis: It is impossible that 'John dropped the milk and Julius is a frog'.
invalid_hypothesis: It is likely that 'John dropped the milk and Julius is a frog'.
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
    0.02::factA.
    0.2::factB.
    0.02::factC.
    
  
    %hop2
    conclusion:-and(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'John dropped the milk and Julius is a frog'.