It is probably not the case that John put down the apple. It is probably not the case that Lily is a frog. It is certain that Brian is a lion. It is probably the case that if either 'John put down the apple' or 'Lily is a frog' but not both then Gertrude is a mouse. It is impossible that if 'Brian is a lion' or 'Lily is a frog' or both then Bernhard is a swan. There is a very good chance that if 'John put down the apple' or 'Brian is a lion' or both then Sandra dropped the milk.
There is a very good chance that 'Brian is a lion and Bernhard is a swan'.
It is impossible that 'Brian is a lion and Bernhard is a swan'.
There is a very good chance that 'Brian is a lion and Bernhard 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
  0.25::factA.
  0.25::factB.
  1.0::factC.
  %hop1
  0.7::factX:-xor(factA,factB).
  0.0::factY:-or(factC,factB).
  0.8::factZ:-or(factA,factC).

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

  query(conclusion).
  
'Brian is a lion and Bernhard is a swan'.