context: It is probably the case that John went to the garden. It is likely that Brian is a rhino. There is little chance that Winona is a sheep. It is improbable that if 'Winona is a sheep and Brian is a rhino' then Greg is gray. We believe that if 'Winona is a sheep and John went to the garden' then Julius is yellow. There is almost no chance that if either 'Winona is a sheep' or 'Brian is a rhino' but not both then Mary took the football.
hypothesis: It is almost certain that 'Julius is yellow' or 'Greg is gray' or both.
valid_hypothesis: It is highly unlikely that 'Julius is yellow' or 'Greg is gray' or both.
invalid_hypothesis: It is almost certain that 'Julius is yellow' or 'Greg is gray' 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
    0.7::factA.
    0.7::factB.
    0.1::factC.
    %hop1
    0.1::factX:-and(factC,factB).
    0.75::factY:-and(factC,factA).
    0.02::factZ:-xor(factC,factB).
  
    %hop2
    conclusion:-or(factY,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is yellow' or 'Greg is gray' or both.