context: It is probable that Bill went to the kitchen. It is probably the case that Lily is gray. It is certain that Greg is a frog.
hypothesis: It is improbable that 'Greg is a frog and Bill went to the kitchen'.
valid_hypothesis: It is probable that 'Greg is a frog and Bill went to the kitchen'.
invalid_hypothesis: It is improbable that 'Greg is a frog and Bill went to the kitchen'.
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
    0.7::factA.
    0.7::factB.
    1.0::factC.
    
  
    %hop2
    conclusion:-and(factC,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is a frog and Bill went to the kitchen'.