It is improbable that Mary went to the kitchen. There is little chance that Winona is a wolf. We believe that Greg is gray. It is probable that if 'Mary went to the kitchen' or 'Winona is a wolf' or both then Yann is thirsty. There is almost no chance that if either 'Mary went to the kitchen' or 'Winona is a wolf' but not both then Fred left the football. We believe that if 'Greg is gray and Winona is a wolf' then Lily is a frog.
Chances are slight that 'Yann is thirsty and Greg is gray'.
Chances are slight that 'Yann is thirsty and Greg is gray'.
It is probably the case that 'Yann is thirsty and Greg is gray'.

  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.
  0.75::factC.
  %hop1
  0.7::factX:-or(factA,factB).
  0.02::factY:-xor(factA,factB).
  0.75::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Yann is thirsty and Greg is gray'.