context: It is unlikely that Lily is gray. There is little chance that Julius is a lion. There is almost no chance that Greg is yellow. It is probably not the case that if 'Julius is a lion and Greg is yellow' then Jason is tired. It is highly unlikely that if either 'Julius is a lion' or 'Greg is yellow' but not both then Mary left the milk. It is highly likely that if 'Julius is a lion and Lily is gray' then Jessica is a cat.
hypothesis: It is certain that 'Greg is yellow' or 'Julius is a lion' or both.
valid_hypothesis: There is little chance that 'Greg is yellow' or 'Julius is a lion' or both.
invalid_hypothesis: It is certain that 'Greg is yellow' or 'Julius is a lion' 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
    0.2::factA.
    0.1::factB.
    0.02::factC.
    %hop1
    0.25::factX:-and(factB,factC).
    0.05::factY:-xor(factB,factC).
    0.9::factZ:-and(factB,factA).
  
    %hop2
    conclusion:-or(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is yellow' or 'Julius is a lion' or both.