There is a very good chance that Brian is a swan. It is impossible that Mary went to the office. There is little chance that Bernhard is white. It is probably not the case that if either 'Mary went to the office' or 'Bernhard is white' but not both then Lily is green. It is highly likely that if 'Brian is a swan and Mary went to the office' then Julius is a lion. It is almost certain that if either 'Bernhard is white' or 'Mary went to the office' but not both then Daniel dropped the milk.
It is impossible that 'Daniel dropped the milk and Mary went to the office'.
It is impossible that 'Daniel dropped the milk and Mary went to the office'.
We believe that 'Daniel dropped the milk and Mary went to the office'.

  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.
  0.0::factB.
  0.1::factC.
  %hop1
  0.25::factX:-xor(factB,factC).
  0.9::factY:-and(factA,factB).
  0.95::factZ:-xor(factC,factB).

  %hop2
  conclusion:-and(factZ,factB).

  query(conclusion).
  
'Daniel dropped the milk and Mary went to the office'.