It is unlikely that Lily is a swan. There is little chance that John discarded the apple. It is highly unlikely that Brian is a lion. There is almost no chance that if 'Brian is a lion and John discarded the apple' then Bernhard is green. It is probably the case that if 'Lily is a swan and Brian is a lion' then Sandra dropped the milk. It is highly likely that if 'Brian is a lion and John discarded the apple' then Mary left the football.
It is highly likely that 'Bernhard is green and Lily is a swan'.
It is impossible that 'Bernhard is green and Lily is a swan'.
It is highly likely that 'Bernhard is green and Lily is a swan'.

  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.
  0.05::factC.
  %hop1
  0.02::factX:-and(factC,factB).
  0.7::factY:-and(factA,factC).
  0.9::factZ:-and(factC,factB).

  %hop2
  conclusion:-and(factX,factA).

  query(conclusion).
  
'Bernhard is green and Lily is a swan'.