We believe that Winona is a sheep. There is a very good chance that Greg is a swan. There is little chance that Yann is hungry. It is highly likely that if 'Winona is a sheep and Greg is a swan' then John grabbed the milk. It is almost certain that if either 'Greg is a swan' or 'Winona is a sheep' but not both then Julius is a rhino. It is probably not the case that if either 'Greg is a swan' or 'Winona is a sheep' but not both then Mary got the football.
It is highly unlikely that 'Winona is a sheep and Mary got the football'.
It is highly unlikely that 'Winona is a sheep and Mary got the football'.
There is a very good chance that 'Winona is a sheep and Mary got 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
  0.75::factA.
  0.8::factB.
  0.1::factC.
  %hop1
  0.9::factX:-and(factA,factB).
  0.95::factY:-xor(factB,factA).
  0.25::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Winona is a sheep and Mary got the football'.