context: Chances are about even that John left the milk. It is certain that Brian is a lion. It is highly likely that Mary is in the hallway.
hypothesis: It is highly likely that 'Mary is in the hallway and Brian is a lion'.
valid_hypothesis: It is highly likely that 'Mary is in the hallway and Brian is a lion'.
invalid_hypothesis: Chances are slight that 'Mary is in the hallway and Brian is a lion'.
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
    0.5::factA.
    1.0::factB.
    0.9::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary is in the hallway and Brian is a lion'.