context: Chances are about even that Mary went to the office. There is almost no chance that John dropped the apple. We believe that Jessica is a cat. It is likely that if 'Jessica is a cat' or 'John dropped the apple' or both then Julius is a swan. We believe that if 'John dropped the apple and Mary went to the office' then Daniel took the milk. It is unlikely that if 'Jessica is a cat' or 'John dropped the apple' or both then Yann is bored.
hypothesis: Chances are slight that 'Yann is bored and Julius is a swan'.
valid_hypothesis: Chances are slight that 'Yann is bored and Julius is a swan'.
invalid_hypothesis: It is almost certain that 'Yann is bored and Julius is a swan'.
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.
    0.02::factB.
    0.75::factC.
    %hop1
    0.7::factX:-or(factC,factB).
    0.75::factY:-and(factB,factA).
    0.2::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-and(factZ,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Yann is bored and Julius is a swan'.