It is almost certain that Winona is a mouse. It is impossible that Brian is a frog. It is highly unlikely that John grabbed the apple. It is certain that if 'Winona is a mouse and Brian is a frog' then Jeff moved to the office. It is highly unlikely that if 'Brian is a frog and Winona is a mouse' then Sumit is thirsty. It is probably not the case that if 'Winona is a mouse' or 'John grabbed the apple' or both then Greg is yellow.
It is highly likely that either 'Greg is yellow' or 'Brian is a frog' but not both.
It is probably not the case that either 'Greg is yellow' or 'Brian is a frog' but not both.
It is highly likely that either 'Greg is yellow' or 'Brian is a frog' but not both.

  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.
  0.0::factB.
  0.05::factC.
  %hop1
  1.0::factX:-and(factA,factB).
  0.05::factY:-and(factB,factA).
  0.25::factZ:-or(factA,factC).

  %hop2
  conclusion:-xor(factZ,factB).

  query(conclusion).
  
Either 'Greg is yellow' or 'Brian is a frog' but not both.