actualize
set-union
with
lebref
by morphism
:set → lebrefset;
:elem → lebref;
∅ → ∅;
++ → ++;
# → #;
{ } → { };
∪ → ∪;
∩ → ∩;
\ → \;
-- → --;
∈ → ∈;
⊆ → ⊆;
a → lref;
b → lref0;
c → lref1;
s → s;
s0 → s0;
s1 → s1;
s2 → s2
end actualize