context: We believe that Lily is a rhino. It is improbable that Bernhard is yellow. We believe that Emily is a cat. It is highly unlikely that if 'Lily is a rhino' or 'Emily is a cat' or both then Jessica is a sheep. It is likely that if either 'Bernhard is yellow' or 'Emily is a cat' but not both then Greg is a swan. There is almost no chance that if 'Lily is a rhino' or 'Emily is a cat' or both then Sandra took the milk.
hypothesis: We believe that 'Bernhard is yellow' or 'Emily is a cat' or both.
valid_hypothesis: We believe that 'Bernhard is yellow' or 'Emily is a cat' or both.
invalid_hypothesis: There is little chance that 'Bernhard is yellow' or 'Emily is a cat' 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
    0.75::factA.
    0.1::factB.
    0.75::factC.
    %hop1
    0.05::factX:-or(factA,factC).
    0.7::factY:-xor(factB,factC).
    0.02::factZ:-or(factA,factC).
  
    %hop2
    conclusion:-or(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is yellow' or 'Emily is a cat' or both.