It is improbable that Julius is yellow. It is improbable that Mary is in the bathroom. There is a very good chance that Greg is green. It is improbable that if 'Mary is in the bathroom' or 'Julius is yellow' or both then Winona is a mouse. We believe that if 'Julius is yellow and Mary is in the bathroom' then Emily is a wolf. It is improbable that if 'Mary is in the bathroom' or 'Greg is green' or both then Bill went to the office.
It is certain that 'Winona is a mouse and Bill went to the office'.
It is impossible that 'Winona is a mouse and Bill went to the office'.
It is certain that 'Winona is a mouse and Bill went 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
  0.1::factA.
  0.1::factB.
  0.8::factC.
  %hop1
  0.1::factX:-or(factB,factA).
  0.75::factY:-and(factA,factB).
  0.1::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Winona is a mouse and Bill went to the office'.