Chances are slight that Jason is bored. It is impossible that Julius is gray. It is certain that Greg is yellow. It is unlikely that if 'Jason is bored' or 'Julius is gray' or both then Brian is a frog. It is certain that if 'Jason is bored and Greg is yellow' then Fred went to the garden. It is highly unlikely that if either 'Greg is yellow' or 'Julius is gray' but not both then Lily is a lion.
There is little chance that 'Jason is bored' or 'Julius is gray' or both.
There is little chance that 'Jason is bored' or 'Julius is gray' or both.
It is certain that 'Jason is bored' or 'Julius is gray' 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
  0.1::factA.
  0.0::factB.
  1.0::factC.
  %hop1
  0.2::factX:-or(factA,factB).
  1.0::factY:-and(factA,factC).
  0.05::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Jason is bored' or 'Julius is gray' or both.