context: We believe that Mary dropped the apple. There is a very good chance that Brian is a lion. Chances are slight that Sandra left the milk.
hypothesis: It is improbable that 'Brian is a lion and Sandra left the milk'.
valid_hypothesis: It is improbable that 'Brian is a lion and Sandra left the milk'.
invalid_hypothesis: It is almost certain that 'Brian is a lion and Sandra left the milk'.
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.
    0.8::factB.
    0.1::factC.
    
  
    %hop2
    conclusion:-and(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a lion and Sandra left the milk'.