context: It is certain that Brian is yellow. It is highly likely that Bernhard is a lion. Chances are slight that Greg is a rhino. It is highly likely that if either 'Brian is yellow' or 'Greg is a rhino' but not both then Lily is green. It is probably the case that if either 'Bernhard is a lion' or 'Brian is yellow' but not both then Jason is tired. There is almost no chance that if either 'Bernhard is a lion' or 'Greg is a rhino' but not both then John discarded the milk.
hypothesis: Chances are about even that 'Brian is yellow' or 'Jason is tired' or both.
valid_hypothesis: It is certain that 'Brian is yellow' or 'Jason is tired' or both.
invalid_hypothesis: Chances are about even that 'Brian is yellow' or 'Jason is tired' 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
    1.0::factA.
    0.9::factB.
    0.1::factC.
    %hop1
    0.9::factX:-xor(factA,factC).
    0.7::factY:-xor(factB,factA).
    0.02::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-or(factA,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is yellow' or 'Jason is tired' or both.