context: There is little chance that Lily is a swan. Chances are slight that Bernhard is yellow. There is almost no chance that Brian is a frog. It is almost certain that if either 'Lily is a swan' or 'Brian is a frog' but not both then Greg is a lion. It is highly unlikely that if 'Brian is a frog' or 'Lily is a swan' or both then Bill went to the office. It is improbable that if either 'Lily is a swan' or 'Bernhard is yellow' but not both then John moved to the garden.
hypothesis: There is almost no chance that 'Lily is a swan and Bernhard is yellow'.
valid_hypothesis: There is almost no chance that 'Lily is a swan and Bernhard is yellow'.
invalid_hypothesis: It is almost certain that 'Lily is a swan 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
    0.1::factA.
    0.1::factB.
    0.02::factC.
    %hop1
    0.95::factX:-xor(factA,factC).
    0.05::factY:-or(factC,factA).
    0.1::factZ:-xor(factA,factB).
  
    %hop2
    conclusion:-and(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is a swan and Bernhard is yellow'.