context: We doubt that Greg is a lion. We doubt that Brian is a rhino. It is probably not the case that John discarded the milk. We doubt that if 'John discarded the milk and Greg is a lion' then Mary moved to the office. It is improbable that if either 'John discarded the milk' or 'Greg is a lion' but not both then Winona is a wolf. It is unlikely that if 'Brian is a rhino' or 'John discarded the milk' or both then Bernhard is white.
hypothesis: We doubt that either 'Mary moved to the office' or 'Greg is a lion' but not both.
valid_hypothesis: We doubt that either 'Mary moved to the office' or 'Greg is a lion' but not both.
invalid_hypothesis: It is almost certain that either 'Mary moved to the office' or 'Greg is a lion' 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.
    0.2::factB.
    0.25::factC.
    %hop1
    0.2::factX:-and(factC,factA).
    0.1::factY:-xor(factC,factA).
    0.2::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-xor(factX,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Mary moved to the office' or 'Greg is a lion' but not both.