There is little chance that Julius is a swan. Chances are slight that Brian is white. It is probably not the case that Greg is a swan. It is highly likely that if 'Greg is a swan and Brian is white' then John went to the garden. It is likely that if 'Greg is a swan and Brian is white' then Sumit is hungry. There is little chance that if 'Brian is white' or 'Julius is a swan' or both then Fred left the apple.
It is probable that 'Fred left the apple and Sumit is hungry'.
It is impossible that 'Fred left the apple and Sumit is hungry'.
It is probable that 'Fred left the apple and Sumit is hungry'.

  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
  0.1::factA.
  0.1::factB.
  0.25::factC.
  %hop1
  0.9::factX:-and(factC,factB).
  0.7::factY:-and(factC,factB).
  0.1::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Fred left the apple and Sumit is hungry'.