We believe that Gertrude is a sheep. It is probably not the case that Brian is white. There is little chance that Bernhard is a rhino. It is highly unlikely that if either 'Bernhard is a rhino' or 'Brian is white' but not both then Mary left the football. It is probably the case that if 'Bernhard is a rhino and Brian is white' then Lily is a rhino. There is almost no chance that if either 'Brian is white' or 'Gertrude is a sheep' but not both then Sandra got the milk.
It is probable that 'Lily is a rhino and Mary left the football'.
It is impossible that 'Lily is a rhino and Mary left the football'.
It is probable that 'Lily is a rhino and Mary left the football'.

  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
  0.75::factA.
  0.25::factB.
  0.1::factC.
  %hop1
  0.05::factX:-xor(factC,factB).
  0.7::factY:-and(factC,factB).
  0.02::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Lily is a rhino and Mary left the football'.