We doubt that Brian is a lion. There is little chance that Mary went to the kitchen. There is a better than even chance that Lily is green. It is probable that if 'Lily is green and Mary went to the kitchen' then Yann is bored. It is probably not the case that if either 'Mary went to the kitchen' or 'Brian is a lion' but not both then Bernhard is yellow. It is unlikely that if either 'Lily is green' or 'Mary went to the kitchen' but not both then Julius is a frog.
There is a better than even chance that either 'Bernhard is yellow' or 'Lily is green' but not both.
There is a better than even chance that either 'Bernhard is yellow' or 'Lily is green' but not both.
There is little chance that either 'Bernhard is yellow' or 'Lily is green' 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
  0.2::factA.
  0.1::factB.
  0.6::factC.
  %hop1
  0.7::factX:-and(factC,factB).
  0.25::factY:-xor(factB,factA).
  0.2::factZ:-xor(factC,factB).

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

  query(conclusion).
  
Either 'Bernhard is yellow' or 'Lily is green' but not both.