context: It is probably not the case that John left the apple. We believe that Bernhard is a swan. We doubt that Julius is a lion.
hypothesis: We believe that 'Bernhard is a swan and John left the apple'.
valid_hypothesis: We doubt that 'Bernhard is a swan and John left the apple'.
invalid_hypothesis: We believe that 'Bernhard is a swan and John left the apple'.
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
    0.25::factA.
    0.75::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-and(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is a swan and John left the apple'.