It is likely that Brian is yellow. There is a better than even chance that Emily is a wolf. Chances are about even that Julius is gray. It is impossible that if either 'Brian is yellow' or 'Julius is gray' but not both then Greg is a swan. It is highly likely that if 'Brian is yellow' or 'Emily is a wolf' or both then Lily is white. It is unlikely that if 'Emily is a wolf and Julius is gray' then Mary left the football.
It is probable that either 'Lily is white' or 'Brian is yellow' but not both.
It is probably not the case that either 'Lily is white' or 'Brian is yellow' but not both.
It is probable that either 'Lily is white' or 'Brian is yellow' 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
  0.7::factA.
  0.6::factB.
  0.5::factC.
  %hop1
  0.0::factX:-xor(factA,factC).
  0.9::factY:-or(factA,factB).
  0.2::factZ:-and(factB,factC).

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

  query(conclusion).
  
Either 'Lily is white' or 'Brian is yellow' but not both.