context: It is improbable that Julius is a swan. It is improbable that Lily is a lion. We doubt that Greg is green. We believe that if 'Greg is green and Lily is a lion' then Mary got the football. It is highly likely that if either 'Lily is a lion' or 'Greg is green' but not both then John went to the garden. It is almost certain that if 'Greg is green and Julius is a swan' then Bernhard is a rhino.
hypothesis: It is probably the case that 'Bernhard is a rhino and Greg is green'.
valid_hypothesis: There is almost no chance that 'Bernhard is a rhino and Greg is green'.
invalid_hypothesis: It is probably the case that 'Bernhard is a rhino and Greg is green'.
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.
    0.1::factB.
    0.2::factC.
    %hop1
    0.75::factX:-and(factC,factB).
    0.9::factY:-xor(factB,factC).
    0.95::factZ:-and(factC,factA).
  
    %hop2
    conclusion:-and(factZ,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is a rhino and Greg is green'.