Chances are slight that Mary grabbed the apple. It is impossible that Jeff went to the garden. There is almost no chance that Bernhard is a swan. There is almost no chance that if 'Bernhard is a swan' or 'Jeff went to the garden' or both then Jessica is a mouse. There is almost no chance that if 'Jeff went to the garden' or 'Mary grabbed the apple' or both then Julius is a frog. It is certain that if 'Bernhard is a swan and Jeff went to the garden' then Greg is a rhino.
It is impossible that 'Jessica is a mouse and Bernhard is a swan'.
It is impossible that 'Jessica is a mouse and Bernhard is a swan'.
There is a very good chance that 'Jessica is a mouse and Bernhard is a swan'.

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

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

  query(conclusion).
  
'Jessica is a mouse and Bernhard is a swan'.