context: There is little chance that Brian is a lion. We doubt that Mary got the football. It is likely that Jeff moved to the office. There is a better than even chance that if either 'Mary got the football' or 'Jeff moved to the office' but not both then John dropped the apple. There is a better than even chance that if either 'Mary got the football' or 'Brian is a lion' but not both then Julius is a frog. There is little chance that if 'Jeff moved to the office' or 'Mary got the football' or both then Bernhard is a swan.
hypothesis: It is almost certain that either 'Brian is a lion' or 'Bernhard is a swan' but not both.
valid_hypothesis: We doubt that either 'Brian is a lion' or 'Bernhard is a swan' but not both.
invalid_hypothesis: It is almost certain that either 'Brian is a lion' or 'Bernhard 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
    0.1::factA.
    0.2::factB.
    0.7::factC.
    %hop1
    0.6::factX:-xor(factB,factC).
    0.6::factY:-xor(factB,factA).
    0.1::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-xor(factA,factZ).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Brian is a lion' or 'Bernhard is a swan' but not both.