context: Chances are about even that Lily is a lion. There is almost no chance that Yann is tired. It is unlikely that Bernhard is yellow. There is a very good chance that if either 'Lily is a lion' or 'Yann is tired' but not both then Julius is a frog. Chances are about even that if 'Bernhard is yellow' or 'Lily is a lion' or both then Sandra got the milk. It is probably not the case that if 'Lily is a lion' or 'Yann is tired' or both then Mary left the football.
hypothesis: There is little chance that 'Lily is a lion and Bernhard is yellow'.
valid_hypothesis: There is little chance that 'Lily is a lion and Bernhard is yellow'.
invalid_hypothesis: It is almost certain that 'Lily is a lion and Bernhard is yellow'.
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.
    0.2::factC.
    %hop1
    0.8::factX:-xor(factA,factB).
    0.5::factY:-or(factC,factA).
    0.25::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-and(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is a lion and Bernhard is yellow'.