context: There is little chance that Mary left the football. There is almost no chance that John dropped the apple. There is almost no chance that Julius is a rhino. It is highly unlikely that if 'John dropped the apple' or 'Julius is a rhino' or both then Winona is a cat. It is certain that if 'Julius is a rhino and John dropped the apple' then Brian is a lion. Chances are about even that if 'John dropped the apple and Julius is a rhino' then Lily is green.
hypothesis: It is likely that 'Julius is a rhino' or 'Lily is green' or both.
valid_hypothesis: There is almost no chance that 'Julius is a rhino' or 'Lily is green' or both.
invalid_hypothesis: It is likely that 'Julius is a rhino' or 'Lily is green' 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.
    0.02::factB.
    0.02::factC.
    %hop1
    0.05::factX:-or(factB,factC).
    1.0::factY:-and(factC,factB).
    0.5::factZ:-and(factB,factC).
  
    %hop2
    conclusion:-or(factC,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is a rhino' or 'Lily is green' or both.