It is highly likely that Mary left the football. Chances are slight that Brian is white. We doubt that Julius is a swan. It is probably the case that if 'Julius is a swan' or 'Brian is white' or both then John discarded the apple. We doubt that if either 'Mary left the football' or 'Brian is white' but not both then Bill went to the garden. It is highly unlikely that if 'Julius is a swan and Brian is white' then Winona is a mouse.
It is impossible that 'Winona is a mouse and Mary left the football'.
It is impossible that 'Winona is a mouse and Mary left the football'.
It is likely that 'Winona is a mouse and Mary left 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
  0.9::factA.
  0.1::factB.
  0.2::factC.
  %hop1
  0.7::factX:-or(factC,factB).
  0.2::factY:-xor(factA,factB).
  0.05::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Winona is a mouse and Mary left the football'.