It is improbable that Brian is yellow. Chances are about even that Bernhard is a swan. It is probable that Yann is hungry. We doubt that if 'Yann is hungry' or 'Brian is yellow' or both then Gertrude is a cat. It is highly likely that if 'Yann is hungry' or 'Brian is yellow' or both then Emily is a wolf. It is probable that if 'Bernhard is a swan' or 'Brian is yellow' or both then Mary moved to the garden.
There is almost no chance that 'Brian is yellow and Gertrude is a cat'.
There is almost no chance that 'Brian is yellow and Gertrude is a cat'.
We believe that 'Brian is yellow and Gertrude is a cat'.

  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.
  0.5::factB.
  0.7::factC.
  %hop1
  0.2::factX:-or(factC,factA).
  0.9::factY:-or(factC,factA).
  0.7::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Brian is yellow and Gertrude is a cat'.