context: It is impossible that Greg is yellow. It is probably the case that Julius is a rhino. There is almost no chance that John went to the garden. It is unlikely that if 'Greg is yellow' or 'Julius is a rhino' or both then Mary picked up the milk. It is impossible that if 'John went to the garden and Julius is a rhino' then Lily is a lion. We doubt that if either 'Greg is yellow' or 'John went to the garden' but not both then Bernhard is green.
hypothesis: Chances are slight that 'Mary picked up the milk and Julius is a rhino'.
valid_hypothesis: Chances are slight that 'Mary picked up the milk and Julius is a rhino'.
invalid_hypothesis: It is certain that 'Mary picked up the milk and Julius is a rhino'.
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
    0.0::factA.
    0.7::factB.
    0.02::factC.
    %hop1
    0.2::factX:-or(factA,factB).
    0.0::factY:-and(factC,factB).
    0.2::factZ:-xor(factA,factC).
  
    %hop2
    conclusion:-and(factX,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary picked up the milk and Julius is a rhino'.