It is improbable that Winona is a wolf. It is highly likely that Greg is a lion. There is a better than even chance that Gertrude is a mouse. It is probably the case that if either 'Greg is a lion' or 'Gertrude is a mouse' but not both then Lily is white. It is probably not the case that if 'Greg is a lion and Gertrude is a mouse' then Brian is a frog. It is probably not the case that if 'Greg is a lion and Winona is a wolf' then John moved to the office.
It is impossible that 'Greg is a lion' or 'Gertrude is a mouse' or both.
It is almost certain that 'Greg is a lion' or 'Gertrude is a mouse' or both.
It is impossible that 'Greg is a lion' or 'Gertrude is a mouse' or both.

  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.
  0.9::factB.
  0.6::factC.
  %hop1
  0.7::factX:-xor(factB,factC).
  0.25::factY:-and(factB,factC).
  0.25::factZ:-and(factB,factA).

  %hop2
  conclusion:-or(factB,factC).

  query(conclusion).
  
'Greg is a lion' or 'Gertrude is a mouse' or both.