From 98b6def950ae4ef237ff52739b995c7fbaa388fc Mon Sep 17 00:00:00 2001
From: David Deng <daviddenghaotian@gmail.com>
Date: Fri, 7 Feb 2025 23:26:37 -0500
Subject: [PATCH] update readme

---
 polymorphism/README.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/polymorphism/README.md b/polymorphism/README.md
index e4dfbdd..6942ee9 100644
--- a/polymorphism/README.md
+++ b/polymorphism/README.md
@@ -7,6 +7,7 @@ The $λ^\diamond$-calculus [1], a refined reachability model that scales to para
 * [`Base`](lambda_diamond_base) -- Base system introducing the new reachability model, lacking type polymorphism.
 * [`Fsub`](f_sub_diamond) -- Bounded type-and-reachability polymorphism.
 * [`Trans`](f_sub_trans) -- Bounded type-and-reachability polymorphism with explicit transitive closure.
+* [`Self Nat`](f_sub_self_nat) -- Bounded type-and-reachability polymorphism with self references and natural numbers.
 
 ```mermaid
 graph TD
@@ -14,9 +15,11 @@ graph TD
       Base
       Fsub
 	  Trans
+	  Self Nat
     end
     Base-->Fsub
 	Base-->Trans
+	Trans-->Self Nat
 ```
 
 ## References