It is certain that John went to the hallway. There is a better than even chance that Mary left the football. It is unlikely that Yann is tired. It is probable that if either 'Yann is tired' or 'John went to the hallway' but not both then Daniel got the apple. It is almost certain that if 'Yann is tired and John went to the hallway' then Sandra is in the kitchen. We believe that if either 'Yann is tired' or 'John went to the hallway' but not both then Bernhard is white.
We believe that 'Mary left the football and Bernhard is white'.
It is probably not the case that 'Mary left the football and Bernhard is white'.
We believe that 'Mary left the football and Bernhard is white'.

  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
  1.0::factA.
  0.6::factB.
  0.2::factC.
  %hop1
  0.7::factX:-xor(factC,factA).
  0.95::factY:-and(factC,factA).
  0.75::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Mary left the football and Bernhard is white'.