context: There is almost no chance that Brian is green. Chances are about even that John went to the hallway. It is almost certain that Greg is yellow.
hypothesis: There is almost no chance that 'Brian is green and John went to the hallway'.
valid_hypothesis: There is almost no chance that 'Brian is green and John went to the hallway'.
invalid_hypothesis: There is a better than even chance that 'Brian is green and John went to the hallway'.
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.
    0.5::factB.
    0.95::factC.
    
  
    %hop2
    conclusion:-and(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is green and John went to the hallway'.