context: It is improbable that Bernhard is a rhino. It is unlikely that Mary picked up the milk. It is highly likely that John took the football.
hypothesis: We doubt that 'John took the football and Mary picked up the milk'.
valid_hypothesis: We doubt that 'John took the football and Mary picked up the milk'.
invalid_hypothesis: We believe that 'John took the football and Mary picked up the milk'.
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
    0.1::factA.
    0.2::factB.
    0.9::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'John took the football and Mary picked up the milk'.