It is improbable that Mary moved to the garden. It is certain that Julius is a frog. We doubt that Jeff left the football. We believe that if 'Jeff left the football and Mary moved to the garden' then Lily is a swan. It is probably not the case that if 'Mary moved to the garden' or 'Jeff left the football' or both then Brian is white. We believe that if 'Julius is a frog and Mary moved to the garden' then Yann is hungry.
It is highly likely that either 'Mary moved to the garden' or 'Julius is a frog' but not both.
It is highly likely that either 'Mary moved to the garden' or 'Julius is a frog' but not both.
It is impossible that either 'Mary moved to the garden' or 'Julius is a frog' but not both.

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

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

  query(conclusion).
  
Either 'Mary moved to the garden' or 'Julius is a frog' but not both.