context: There is almost no chance that Brian is a lion. There is almost no chance that John got the apple. We doubt that Fred is in the cinema. It is impossible that if 'Brian is a lion' or 'Fred is in the cinema' or both then Bernhard is a frog. There is almost no chance that if either 'Fred is in the cinema' or 'John got the apple' but not both then Emily is a mouse. It is highly likely that if 'John got the apple and Brian is a lion' then Julius is white.
hypothesis: It is likely that either 'Emily is a mouse' or 'Bernhard is a frog' but not both.
valid_hypothesis: It is impossible that either 'Emily is a mouse' or 'Bernhard is a frog' but not both.
invalid_hypothesis: It is likely that either 'Emily is a mouse' or 'Bernhard is a frog' 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
    0.02::factA.
    0.02::factB.
    0.2::factC.
    %hop1
    0.0::factX:-or(factA,factC).
    0.02::factY:-xor(factC,factB).
    0.9::factZ:-and(factB,factA).
  
    %hop2
    conclusion:-xor(factY,factX).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Emily is a mouse' or 'Bernhard is a frog' but not both.