It is impossible that Julius is yellow. It is impossible that Bernhard is gray. We believe that Lily is a swan. It is likely that if 'Bernhard is gray' or 'Julius is yellow' or both then Greg is a swan. It is probably not the case that if 'Lily is a swan and Julius is yellow' then Emily is a sheep. It is almost certain that if either 'Julius is yellow' or 'Lily is a swan' but not both then John left the milk.
It is impossible that 'Emily is a sheep' or 'Julius is yellow' or both.
It is impossible that 'Emily is a sheep' or 'Julius is yellow' or both.
It is highly likely that 'Emily is a sheep' or 'Julius is yellow' or 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
  0.0::factA.
  0.0::factB.
  0.75::factC.
  %hop1
  0.7::factX:-or(factB,factA).
  0.25::factY:-and(factC,factA).
  0.95::factZ:-xor(factA,factC).

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

  query(conclusion).
  
'Emily is a sheep' or 'Julius is yellow' or both.