context: It is impossible that Brian is a swan. There is almost no chance that Greg is white. It is almost certain that Mary left the apple.
hypothesis: It is highly likely that 'Greg is white and Brian is a swan'.
valid_hypothesis: It is impossible that 'Greg is white and Brian is a swan'.
invalid_hypothesis: It is highly likely that 'Greg is white and Brian is a swan'.
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.
    0.02::factB.
    0.95::factC.
    
  
    %hop2
    conclusion:-and(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is white and Brian is a swan'.