Chances are about even that Brian is green. It is certain that Bernhard is a swan. It is probably the case that Lily is yellow. It is probable that if either 'Brian is green' or 'Lily is yellow' but not both then Greg is a swan. We believe that if 'Brian is green and Lily is yellow' then Mary moved to the garden. It is improbable that if either 'Bernhard is a swan' or 'Lily is yellow' but not both then John left the football.
There is almost no chance that 'Lily is yellow' or 'Bernhard is a swan' or both.
It is certain that 'Lily is yellow' or 'Bernhard is a swan' or both.
There is almost no chance that 'Lily is yellow' or 'Bernhard is a swan' 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
  0.5::factA.
  1.0::factB.
  0.7::factC.
  %hop1
  0.7::factX:-xor(factA,factC).
  0.75::factY:-and(factA,factC).
  0.1::factZ:-xor(factB,factC).

  %hop2
  conclusion:-or(factC,factB).

  query(conclusion).
  
'Lily is yellow' or 'Bernhard is a swan' or both.