diff --git a/immutable_vec/README.md b/immutable_vec/README.md
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@@ -1,10 +1,11 @@
 # Immutable Vector
 
-Based on Clojure's [persistent vector](https://hypirion.com/musings/understanding-persistent-vector-pt-1).
-
-Currently, only `push`, `set` and `get` are implemented, alongside with some iteration functions.
-
-## TODO
-
-- Add `insert` and `delete`.
-- Support tail optimization.
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+Based on *RRB Vector: A Practical General Purpose Immutable Sequence, ICFP'15*.
+
+It supports normal vector operations ($m$ is the branching factor and $n$ is the number of elements):
+- Indexing in $O(\log_2{m} \cdot \log_m{n})$
+- Updating in $O(m \cdot \log_m{n})$
+- Removal in $O(m^2 \cdot \log_m{n})$
+- Appending in $O(m \cdot \log_m{n})$
+- Splitting in $O(m \cdot \log_m{n})$
+- Concatenation in $O(m^2 \cdot \log_m{n})$
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