It is improbable that Julius is a swan. It is improbable that Jessica is a mouse. Chances are slight that Greg is green. It is improbable that if 'Julius is a swan' or 'Jessica is a mouse' or both then Sandra took the football. It is probably not the case that if 'Julius is a swan and Jessica is a mouse' then Brian is a rhino. Chances are slight that if 'Greg is green and Jessica is a mouse' then John went to the bedroom.
There is almost no chance that 'Julius is a swan and Sandra took the football'.
There is almost no chance that 'Julius is a swan and Sandra took the football'.
It is probable that 'Julius is a swan and Sandra took 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
  0.1::factA.
  0.1::factB.
  0.1::factC.
  %hop1
  0.1::factX:-or(factA,factB).
  0.25::factY:-and(factA,factB).
  0.1::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Julius is a swan and Sandra took the football'.