It is probable that Sumit is bored. It is probably not the case that Greg is a frog. Chances are about even that John moved to the office. There is little chance that if 'Sumit is bored and Greg is a frog' then Bernhard is a lion. We believe that if either 'Sumit is bored' or 'John moved to the office' but not both then Fred dropped the apple. It is impossible that if either 'Greg is a frog' or 'Sumit is bored' but not both then Brian is green.
It is likely that 'Brian is green' or 'Greg is a frog' or both.
It is probably not the case that 'Brian is green' or 'Greg is a frog' or both.
It is likely that 'Brian is green' or 'Greg is a frog' or 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
  0.7::factA.
  0.25::factB.
  0.5::factC.
  %hop1
  0.1::factX:-and(factA,factB).
  0.75::factY:-xor(factA,factC).
  0.0::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Brian is green' or 'Greg is a frog' or both.