context: There is a very good chance that Brian is gray. It is certain that Lily is white. There is a better than even chance that Julius is a frog.
hypothesis: It is improbable that 'Brian is gray and Lily is white'.
valid_hypothesis: There is a very good chance that 'Brian is gray and Lily is white'.
invalid_hypothesis: It is improbable that 'Brian is gray and Lily is white'.
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
    0.8::factA.
    1.0::factB.
    0.6::factC.
    
  
    %hop2
    conclusion:-and(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is gray and Lily is white'.