context: There is little chance that John moved to the garden. We believe that Greg is a swan. There is a better than even chance that Bernhard is green. It is impossible that if 'Bernhard is green and Greg is a swan' then Mary got the apple. It is highly likely that if either 'John moved to the garden' or 'Greg is a swan' but not both then Julius is gray. We doubt that if 'John moved to the garden and Greg is a swan' then Brian is a swan.
hypothesis: It is highly likely that 'Brian is a swan' or 'Mary got the apple' or both.
valid_hypothesis: There is almost no chance that 'Brian is a swan' or 'Mary got the apple' or both.
invalid_hypothesis: It is highly likely that 'Brian is a swan' or 'Mary got the apple' or 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
    0.1::factA.
    0.75::factB.
    0.6::factC.
    %hop1
    0.0::factX:-and(factC,factB).
    0.9::factY:-xor(factA,factB).
    0.2::factZ:-and(factA,factB).
  
    %hop2
    conclusion:-or(factZ,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a swan' or 'Mary got the apple' or both.