context: It is improbable that Brian is gray. It is almost certain that Winona is a mouse. Chances are about even that Yann is hungry. It is improbable that if 'Yann is hungry' or 'Winona is a mouse' or both then Lily is white. Chances are about even that if either 'Winona is a mouse' or 'Brian is gray' but not both then Greg is a swan. It is certain that if 'Winona is a mouse and Yann is hungry' then John dropped the milk.
hypothesis: It is almost certain that 'Winona is a mouse' or 'Yann is hungry' or both.
valid_hypothesis: It is almost certain that 'Winona is a mouse' or 'Yann is hungry' or both.
invalid_hypothesis: It is impossible that 'Winona is a mouse' or 'Yann is hungry' or both.
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.
    0.95::factB.
    0.5::factC.
    %hop1
    0.1::factX:-or(factC,factB).
    0.5::factY:-xor(factB,factA).
    1.0::factZ:-and(factB,factC).
  
    %hop2
    conclusion:-or(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Winona is a mouse' or 'Yann is hungry' or both.