It is likely that Lily is a swan. It is highly likely that Bernhard is a rhino. There is little chance that Yann is hungry. Chances are about even that if 'Bernhard is a rhino and Yann is hungry' then Jessica is a cat. There is a better than even chance that if 'Lily is a swan' or 'Bernhard is a rhino' or both then Brian is a lion. We believe that if either 'Yann is hungry' or 'Lily is a swan' but not both then Mary moved to the garden.
We believe that 'Mary moved to the garden and Brian is a lion'.
It is probably not the case that 'Mary moved to the garden and Brian is a lion'.
We believe that 'Mary moved to the garden and Brian is a lion'.

  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.
  0.9::factB.
  0.1::factC.
  %hop1
  0.5::factX:-and(factB,factC).
  0.6::factY:-or(factA,factB).
  0.75::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Mary moved to the garden and Brian is a lion'.