It is almost certain that Yann is tired. It is certain that Mary left the football. There is a very good chance that Bernhard is a frog. There is little chance that if either 'Mary left the football' or 'Yann is tired' but not both then John went to the office. It is probable that if 'Mary left the football and Bernhard is a frog' then Winona is a mouse. We doubt that if either 'Yann is tired' or 'Bernhard is a frog' but not both then Julius is yellow.
It is highly unlikely that 'Julius is yellow and Yann is tired'.
It is highly unlikely that 'Julius is yellow and Yann is tired'.
It is probable that 'Julius is yellow and Yann is tired'.

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

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

  query(conclusion).
  
'Julius is yellow and Yann is tired'.