context: There is little chance that Greg is a swan. It is highly unlikely that Brian is gray. There is almost no chance that John left the football. It is almost certain that if 'Brian is gray' or 'Greg is a swan' or both then Lily is a rhino. Chances are slight that if 'Greg is a swan and Brian is gray' then Winona is a mouse. It is impossible that if 'Brian is gray and Greg is a swan' then Julius is a lion.
hypothesis: It is highly unlikely that 'Brian is gray' or 'Winona is a mouse' or both.
valid_hypothesis: It is highly unlikely that 'Brian is gray' or 'Winona is a mouse' or both.
invalid_hypothesis: It is highly likely that 'Brian is gray' or 'Winona is a mouse' 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.
    0.05::factB.
    0.02::factC.
    %hop1
    0.95::factX:-or(factB,factA).
    0.1::factY:-and(factA,factB).
    0.0::factZ:-and(factB,factA).
  
    %hop2
    conclusion:-or(factB,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is gray' or 'Winona is a mouse' or both.