context: Chances are slight that Julius is a swan. There is almost no chance that Sandra grabbed the milk. It is likely that Brian is a swan. It is highly likely that if 'Julius is a swan and Sandra grabbed the milk' then Jeff went to the garden. It is impossible that if 'Sandra grabbed the milk' or 'Julius is a swan' or both then Mary got the apple. It is highly unlikely that if 'Brian is a swan and Julius is a swan' then Jason is tired.
hypothesis: It is probable that 'Sandra grabbed the milk and Julius is a swan'.
valid_hypothesis: It is impossible that 'Sandra grabbed the milk and Julius is a swan'.
invalid_hypothesis: It is probable that 'Sandra grabbed the milk and Julius 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
    0.1::factA.
    0.02::factB.
    0.7::factC.
    %hop1
    0.9::factX:-and(factA,factB).
    0.0::factY:-or(factB,factA).
    0.05::factZ:-and(factC,factA).
  
    %hop2
    conclusion:-and(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra grabbed the milk and Julius is a swan'.