context: It is probable that Greg is a rhino. It is highly unlikely that John moved to the garden. There is a very good chance that Bernhard is a lion. We doubt that if either 'Bernhard is a lion' or 'John moved to the garden' but not both then Mary went to the bedroom. We believe that if either 'Bernhard is a lion' or 'Greg is a rhino' but not both then Lily is a lion. There is almost no chance that if either 'Bernhard is a lion' or 'Greg is a rhino' but not both then Brian is yellow.
hypothesis: It is probably not the case that either 'Bernhard is a lion' or 'John moved to the garden' but not both.
valid_hypothesis: We believe that either 'Bernhard is a lion' or 'John moved to the garden' but not both.
invalid_hypothesis: It is probably not the case that either 'Bernhard is a lion' or 'John moved to the garden' 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
    0.7::factA.
    0.05::factB.
    0.8::factC.
    %hop1
    0.2::factX:-xor(factC,factB).
    0.75::factY:-xor(factC,factA).
    0.02::factZ:-xor(factC,factA).
  
    %hop2
    conclusion:-xor(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Bernhard is a lion' or 'John moved to the garden' but not both.