It is probably not the case that John went to the kitchen. It is unlikely that Bernhard is green. It is highly unlikely that Brian is a rhino. It is highly unlikely that if 'Brian is a rhino' or 'Bernhard is green' or both then Mary moved to the office. It is certain that if either 'Bernhard is green' or 'Brian is a rhino' but not both then Lily is a swan. There is little chance that if 'John went to the kitchen' or 'Bernhard is green' or both then Fred left the football.
There is almost no chance that 'Lily is a swan and Fred left the football'.
There is almost no chance that 'Lily is a swan and Fred left the football'.
We believe that 'Lily is a swan and Fred left 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
  0.25::factA.
  0.2::factB.
  0.05::factC.
  %hop1
  0.05::factX:-or(factC,factB).
  1.0::factY:-xor(factB,factC).
  0.1::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Lily is a swan and Fred left the football'.