It is highly unlikely that Jeff moved to the office. Chances are about even that Jason is tired. It is highly unlikely that Brian is a frog. There is little chance that if 'Jeff moved to the office and Brian is a frog' then Bernhard is gray. It is certain that if either 'Jeff moved to the office' or 'Brian is a frog' but not both then Julius is a rhino. Chances are slight that if either 'Brian is a frog' or 'Jason is tired' but not both then Greg is a lion.
It is impossible that 'Greg is a lion and Jeff moved to the office'.
It is impossible that 'Greg is a lion and Jeff moved to the office'.
We believe that 'Greg is a lion and Jeff moved to the office'.

  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
  0.05::factA.
  0.5::factB.
  0.05::factC.
  %hop1
  0.1::factX:-and(factA,factC).
  1.0::factY:-xor(factA,factC).
  0.1::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Greg is a lion and Jeff moved to the office'.