context: There is almost no chance that Julius is gray. There is little chance that Mary discarded the milk. It is certain that Jessica is a mouse. There is a very good chance that if either 'Jessica is a mouse' or 'Mary discarded the milk' but not both then Gertrude is a sheep. It is probable that if either 'Mary discarded the milk' or 'Jessica is a mouse' but not both then Brian is yellow. There is almost no chance that if 'Jessica is a mouse' or 'Mary discarded the milk' or both then Sandra dropped the milk.
hypothesis: There is a better than even chance that 'Brian is yellow' or 'Julius is gray' or both.
valid_hypothesis: There is a better than even chance that 'Brian is yellow' or 'Julius is gray' or both.
invalid_hypothesis: It is impossible that 'Brian is yellow' or 'Julius is gray' 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
    0.02::factA.
    0.1::factB.
    1.0::factC.
    %hop1
    0.8::factX:-xor(factC,factB).
    0.7::factY:-xor(factB,factC).
    0.02::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-or(factY,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is yellow' or 'Julius is gray' or both.