context: There is a very good chance that Brian is a rhino. It is improbable that John dropped the milk. Chances are about even that Bernhard is a swan.
hypothesis: Chances are about even that 'Brian is a rhino and Bernhard is a swan'.
valid_hypothesis: Chances are about even that 'Brian is a rhino and Bernhard is a swan'.
invalid_hypothesis: It is highly unlikely that 'Brian is a rhino and Bernhard is a swan'.
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
    0.8::factA.
    0.1::factB.
    0.5::factC.
    
  
    %hop2
    conclusion:-and(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a rhino and Bernhard is a swan'.