context: It is probable that Lily is a rhino. Chances are slight that Winona is a wolf. We doubt that John went to the kitchen. It is improbable that if either 'John went to the kitchen' or 'Lily is a rhino' but not both then Greg is gray. It is unlikely that if either 'Winona is a wolf' or 'John went to the kitchen' but not both then Daniel left the apple. It is certain that if 'Winona is a wolf' or 'John went to the kitchen' or both then Brian is a swan.
hypothesis: It is probably not the case that either 'Daniel left the apple' or 'Brian is a swan' but not both.
valid_hypothesis: It is probably not the case that either 'Daniel left the apple' or 'Brian is a swan' but not both.
invalid_hypothesis: It is almost certain that either 'Daniel left the apple' or 'Brian is a swan' 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.
    0.1::factB.
    0.2::factC.
    %hop1
    0.1::factX:-xor(factC,factA).
    0.2::factY:-xor(factB,factC).
    1.0::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-xor(factY,factZ).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Daniel left the apple' or 'Brian is a swan' but not both.