context: Chances are about even that Lily is a swan. It is improbable that Yann is tired. We believe that Bernhard is a lion.
hypothesis: Chances are slight that 'Bernhard is a lion and Yann is tired'.
valid_hypothesis: Chances are slight that 'Bernhard is a lion and Yann is tired'.
invalid_hypothesis: It is certain that 'Bernhard is a lion and Yann is tired'.
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.
    0.1::factB.
    0.75::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is a lion and Yann is tired'.