We believe that Greg is a swan. It is impossible that Julius is white. It is probably the case that Mary got the football. It is likely that if 'Greg is a swan' or 'Julius is white' or both then Lily is a lion. It is highly unlikely that if either 'Mary got the football' or 'Greg is a swan' but not both then Jeff moved to the garden. There is almost no chance that if 'Julius is white and Greg is a swan' then Gertrude is a cat.
There is almost no chance that 'Jeff moved to the garden and Greg is a swan'.
There is almost no chance that 'Jeff moved to the garden and Greg is a swan'.
It is probable that 'Jeff moved to the garden and Greg 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
  0.75::factA.
  0.0::factB.
  0.7::factC.
  %hop1
  0.7::factX:-or(factA,factB).
  0.05::factY:-xor(factC,factA).
  0.02::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Jeff moved to the garden and Greg is a swan'.