It is probably the case that Jessica is a mouse. Chances are about even that Mary went to the office. Chances are slight that Brian is green. We believe that if 'Jessica is a mouse' or 'Mary went to the office' or both then John dropped the apple. There is a better than even chance that if 'Brian is green' or 'Mary went to the office' or both then Bernhard is a rhino. It is probably not the case that if either 'Brian is green' or 'Jessica is a mouse' but not both then Lily is green.
It is highly unlikely that 'Mary went to the office and Brian is green'.
It is highly unlikely that 'Mary went to the office and Brian is green'.
It is highly likely that 'Mary went to the office and Brian is green'.

  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.
  0.5::factB.
  0.1::factC.
  %hop1
  0.75::factX:-or(factA,factB).
  0.6::factY:-or(factC,factB).
  0.25::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Mary went to the office and Brian is green'.