actualize set-union
with classname
by morphism : elem → classname; : set → classnameset; ∅ → ∅; ++ → ++; # → #; { } → { }; ∪ → ∪; ∩ → ∩; \ → \; -- → --; ∈ → ∈; ⊆ → ⊆; a → class;
b → class0; c → class1; s → claset; s0 → claset0; s1 → claset1; s2 → claset2;
end actualize