context: We believe that Bernhard is a frog. It is probably the case that Winona is a wolf. There is a better than even chance that Jeff went to the hallway. It is probably the case that if either 'Bernhard is a frog' or 'Jeff went to the hallway' but not both then Brian is a rhino. There is almost no chance that if 'Jeff went to the hallway' or 'Winona is a wolf' or both then Julius is a swan. It is improbable that if 'Winona is a wolf' or 'Jeff went to the hallway' or both then Greg is yellow.
hypothesis: There is a better than even chance that either 'Greg is yellow' or 'Winona is a wolf' but not both.
valid_hypothesis: There is a better than even chance that either 'Greg is yellow' or 'Winona is a wolf' but not both.
invalid_hypothesis: There is little chance that either 'Greg is yellow' or 'Winona is a wolf' 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.
    0.7::factB.
    0.6::factC.
    %hop1
    0.7::factX:-xor(factA,factC).
    0.02::factY:-or(factC,factB).
    0.1::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-xor(factZ,factB).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Greg is yellow' or 'Winona is a wolf' but not both.