We believe that Winona is a cat. There is almost no chance that Lily is white. It is certain that Bernhard is a swan. We believe that if 'Bernhard is a swan and Winona is a cat' then John took the football. We doubt that if 'Lily is white and Winona is a cat' then Gertrude is a sheep. We doubt that if 'Bernhard is a swan' or 'Lily is white' or both then Sandra dropped the milk.
There is almost no chance that 'Winona is a cat and Lily is white'.
There is almost no chance that 'Winona is a cat and Lily is white'.
It is almost certain that 'Winona is a cat and Lily is white'.

  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.
  0.02::factB.
  1.0::factC.
  %hop1
  0.75::factX:-and(factC,factA).
  0.2::factY:-and(factB,factA).
  0.2::factZ:-or(factC,factB).

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

  query(conclusion).
  
'Winona is a cat and Lily is white'.