context: It is probably the case that Lily is a frog. It is highly likely that Jessica is a mouse. It is probable that Brian is yellow. It is almost certain that if 'Jessica is a mouse' or 'Brian is yellow' or both then John got the milk. It is improbable that if 'Brian is yellow' or 'Jessica is a mouse' or both then Julius is gray. It is probable that if either 'Lily is a frog' or 'Brian is yellow' but not both then Mary went to the garden.
hypothesis: There is a very good chance that either 'Brian is yellow' or 'Jessica is a mouse' but not both.
valid_hypothesis: It is probably not the case that either 'Brian is yellow' or 'Jessica is a mouse' but not both.
invalid_hypothesis: There is a very good chance that either 'Brian is yellow' or 'Jessica is a mouse' 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
    0.7::factA.
    0.9::factB.
    0.7::factC.
    %hop1
    0.95::factX:-or(factB,factC).
    0.1::factY:-or(factC,factB).
    0.7::factZ:-xor(factA,factC).
  
    %hop2
    conclusion:-xor(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Brian is yellow' or 'Jessica is a mouse' but not both.