context: We believe that Bernhard is a swan. It is highly likely that Julius is a rhino. It is certain that Sandra took the milk. It is probable that if 'Sandra took the milk and Bernhard is a swan' then Lily is a lion. It is certain that if either 'Julius is a rhino' or 'Sandra took the milk' but not both then Mary grabbed the apple. It is unlikely that if 'Bernhard is a swan and Julius is a rhino' then Brian is white.
hypothesis: Chances are slight that 'Sandra took the milk and Mary grabbed the apple'.
valid_hypothesis: Chances are slight that 'Sandra took the milk and Mary grabbed the apple'.
invalid_hypothesis: It is highly likely that 'Sandra took the milk and Mary grabbed the apple'.
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.
    0.9::factB.
    1.0::factC.
    %hop1
    0.7::factX:-and(factC,factA).
    1.0::factY:-xor(factB,factC).
    0.2::factZ:-and(factA,factB).
  
    %hop2
    conclusion:-and(factC,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra took the milk and Mary grabbed the apple'.