We doubt that Mary went to the office. It is certain that Daniel dropped the apple. We believe that Julius is white. It is improbable that if 'Mary went to the office and Daniel dropped the apple' then Greg is a rhino. It is highly likely that if 'Mary went to the office and Daniel dropped the apple' then Bernhard is green. It is unlikely that if 'Mary went to the office and Daniel dropped the apple' then Lily is a swan.
It is certain that 'Bernhard is green and Mary went to the office'.
It is unlikely that 'Bernhard is green and Mary went to the office'.
It is certain that 'Bernhard is green 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
  0.2::factA.
  1.0::factB.
  0.75::factC.
  %hop1
  0.1::factX:-and(factA,factB).
  0.9::factY:-and(factA,factB).
  0.2::factZ:-and(factA,factB).

  %hop2
  conclusion:-and(factY,factA).

  query(conclusion).
  
'Bernhard is green and Mary went to the office'.