There is a very good chance that Julius is a frog. It is improbable that Mary moved to the office. It is highly unlikely that Sandra is in the kitchen. It is probably not the case that if either 'Julius is a frog' or 'Sandra is in the kitchen' but not both then Lily is a swan. Chances are slight that if 'Julius is a frog' or 'Mary moved to the office' or both then Gertrude is a mouse. It is highly unlikely that if either 'Julius is a frog' or 'Sandra is in the kitchen' but not both then John grabbed the apple.
There is little chance that 'Julius is a frog and Mary moved to the office'.
There is little chance that 'Julius is a frog and Mary moved to the office'.
It is likely that 'Julius is a frog and Mary moved to the office'.

  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
  0.8::factA.
  0.1::factB.
  0.05::factC.
  %hop1
  0.25::factX:-xor(factA,factC).
  0.1::factY:-or(factA,factB).
  0.05::factZ:-xor(factA,factC).

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

  query(conclusion).
  
'Julius is a frog and Mary moved to the office'.