actualize
bag-union
with
file-id
by morphism
:bag → fidbag;
:elem → fid;
∅ → ∅;
++ → ++;
count → count;
{ } → { };
-- → --;
∪ → ∪;
\ → \;
# → #;
∈ → ∈;
⊆ → ⊆;
bag → fidb;
bag0 → fidb0;
bag1 → fidb1;
bag2 → fidb2;
a → fid;
b → fid0;
c → fid1
end actualize