context: We believe that Winona is a wolf. It is probably not the case that Lily is green. It is almost certain that Daniel got the milk. There is little chance that if 'Winona is a wolf and Lily is green' then Greg is a rhino. It is improbable that if 'Daniel got the milk and Winona is a wolf' then Brian is yellow. It is likely that if either 'Daniel got the milk' or 'Lily is green' but not both then Julius is green.
hypothesis: Chances are slight that either 'Greg is a rhino' or 'Brian is yellow' but not both.
valid_hypothesis: Chances are slight that either 'Greg is a rhino' or 'Brian is yellow' but not both.
invalid_hypothesis: There is a very good chance that either 'Greg is a rhino' or 'Brian is yellow' but not 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
    0.75::factA.
    0.25::factB.
    0.95::factC.
    %hop1
    0.1::factX:-and(factA,factB).
    0.1::factY:-and(factC,factA).
    0.7::factZ:-xor(factC,factB).
  
    %hop2
    conclusion:-xor(factX,factY).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Greg is a rhino' or 'Brian is yellow' but not both.