It is probable that Mary left the football. There is a very good chance that Winona is a mouse. Chances are about even that Bill went to the kitchen. There is a very good chance that if either 'Mary left the football' or 'Winona is a mouse' but not both then Bernhard is a swan. It is unlikely that if 'Winona is a mouse' or 'Bill went to the kitchen' or both then Lily is a swan. It is improbable that if 'Mary left the football and Bill went to the kitchen' then Julius is yellow.
It is probably the case that 'Bill went to the kitchen and Julius is yellow'.
It is highly unlikely that 'Bill went to the kitchen and Julius is yellow'.
It is probably the case that 'Bill went to the kitchen and Julius is yellow'.

  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
  0.7::factA.
  0.8::factB.
  0.5::factC.
  %hop1
  0.8::factX:-xor(factA,factB).
  0.2::factY:-or(factB,factC).
  0.1::factZ:-and(factA,factC).

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

  query(conclusion).
  
'Bill went to the kitchen and Julius is yellow'.