context: We believe that Brian is gray. It is likely that Emily is a sheep. It is likely that Greg is a lion.
hypothesis: There is almost no chance that 'Greg is a lion and Emily is a sheep'.
valid_hypothesis: Chances are about even that 'Greg is a lion and Emily is a sheep'.
invalid_hypothesis: There is almost no chance that 'Greg is a lion and Emily is a sheep'.
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
    0.75::factA.
    0.7::factB.
    0.7::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is a lion and Emily is a sheep'.