It is highly likely that Mary got the football. We believe that Yann is thirsty. There is a very good chance that Bernhard is white. There is almost no chance that if 'Yann is thirsty' or 'Bernhard is white' or both then Brian is a rhino. It is highly unlikely that if 'Bernhard is white' or 'Mary got the football' or both then Julius is green. We believe that if either 'Mary got the football' or 'Yann is thirsty' but not both then Greg is a lion.
There is almost no chance that 'Bernhard is white' or 'Brian is a rhino' or both.
There is a very good chance that 'Bernhard is white' or 'Brian is a rhino' or both.
There is almost no chance that 'Bernhard is white' or 'Brian is a rhino' 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
  0.9::factA.
  0.75::factB.
  0.8::factC.
  %hop1
  0.02::factX:-or(factB,factC).
  0.05::factY:-or(factC,factA).
  0.75::factZ:-xor(factA,factB).

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

  query(conclusion).
  
'Bernhard is white' or 'Brian is a rhino' or both.