We believe that Sumit is tired. It is almost certain that Sandra left the milk. It is highly unlikely that Greg is yellow. It is certain that if 'Sumit is tired' or 'Sandra left the milk' or both then Lily is a lion. It is highly unlikely that if 'Greg is yellow' or 'Sumit is tired' or both then Mary went to the bedroom. It is probable that if 'Greg is yellow and Sandra left the milk' then Brian is a rhino.
It is impossible that 'Mary went to the bedroom and Greg is yellow'.
It is impossible that 'Mary went to the bedroom and Greg is yellow'.
It is certain that 'Mary went to the bedroom 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
  0.75::factA.
  0.95::factB.
  0.05::factC.
  %hop1
  1.0::factX:-or(factA,factB).
  0.05::factY:-or(factC,factA).
  0.7::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Mary went to the bedroom and Greg is yellow'.