context: There is almost no chance that Bernhard is a frog. There is almost no chance that Mary moved to the garden. We believe that Gertrude is a mouse. It is highly likely that if 'Bernhard is a frog' or 'Mary moved to the garden' or both then Fred is in the school. It is impossible that if 'Gertrude is a mouse' or 'Mary moved to the garden' or both then Brian is yellow. It is highly unlikely that if 'Mary moved to the garden' or 'Bernhard is a frog' or both then John left the milk.
hypothesis: There is almost no chance that 'Brian is yellow' or 'Bernhard is a frog' or both.
valid_hypothesis: There is almost no chance that 'Brian is yellow' or 'Bernhard is a frog' or both.
invalid_hypothesis: It is almost certain that 'Brian is yellow' or 'Bernhard is a frog' 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.
    0.02::factB.
    0.75::factC.
    %hop1
    0.9::factX:-or(factA,factB).
    0.0::factY:-or(factC,factB).
    0.05::factZ:-or(factB,factA).
  
    %hop2
    conclusion:-or(factY,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is yellow' or 'Bernhard is a frog' or both.