It is probably not the case that Greg is green. It is improbable that Lily is yellow. It is probably not the case that Julius is a swan. It is likely that if either 'Lily is yellow' or 'Julius is a swan' but not both then Brian is a rhino. It is probably the case that if 'Greg is green and Julius is a swan' then John went to the garden. It is improbable that if 'Lily is yellow and Julius is a swan' then Fred put down the apple.
It is probably not the case that either 'Julius is a swan' or 'Fred put down the apple' but not both.
It is probably not the case that either 'Julius is a swan' or 'Fred put down the apple' but not both.
It is almost certain that either 'Julius is a swan' or 'Fred put down the apple' 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
  0.25::factA.
  0.1::factB.
  0.25::factC.
  %hop1
  0.7::factX:-xor(factB,factC).
  0.7::factY:-and(factA,factC).
  0.1::factZ:-and(factB,factC).

  %hop2
  conclusion:-xor(factC,factZ).

  query(conclusion).
  
Either 'Julius is a swan' or 'Fred put down the apple' but not both.