context: We doubt that Greg is a swan. It is almost certain that Julius is yellow. It is probable that Daniel dropped the apple. There is little chance that if 'Daniel dropped the apple' or 'Greg is a swan' or both then Emily is a cat. It is likely that if 'Daniel dropped the apple and Greg is a swan' then Mary went to the hallway. There is almost no chance that if either 'Greg is a swan' or 'Daniel dropped the apple' but not both then Lily is gray.
hypothesis: It is probably not the case that either 'Julius is yellow' or 'Daniel dropped the apple' but not both.
valid_hypothesis: It is probably not the case that either 'Julius is yellow' or 'Daniel dropped the apple' but not both.
invalid_hypothesis: It is probably the case that either 'Julius is yellow' or 'Daniel dropped the apple' 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
    0.2::factA.
    0.95::factB.
    0.7::factC.
    %hop1
    0.1::factX:-or(factC,factA).
    0.7::factY:-and(factC,factA).
    0.02::factZ:-xor(factA,factC).
  
    %hop2
    conclusion:-xor(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Julius is yellow' or 'Daniel dropped the apple' but not both.