It is likely that Daniel put down the milk. It is probable that Greg is yellow. It is probably the case that Bernhard is a frog. It is certain that if 'Greg is yellow and Bernhard is a frog' then Jason is tired. We believe that if either 'Bernhard is a frog' or 'Greg is yellow' but not both then Julius is white. It is certain that if either 'Daniel put down the milk' or 'Bernhard is a frog' but not both then Bill moved to the office.
Chances are about even that 'Daniel put down the milk and Greg is yellow'.
Chances are about even that 'Daniel put down the milk and Greg is yellow'.
It is certain that 'Daniel put down the milk and Greg 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.
  0.7::factB.
  0.7::factC.
  %hop1
  1.0::factX:-and(factB,factC).
  0.75::factY:-xor(factC,factB).
  1.0::factZ:-xor(factA,factC).

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

  query(conclusion).
  
'Daniel put down the milk and Greg is yellow'.