diff --git a/MEV_on_Arbitrum/README.md b/MEV_on_Arbitrum/README.md
index ae49f81..092b83c 100644
--- a/MEV_on_Arbitrum/README.md
+++ b/MEV_on_Arbitrum/README.md
@@ -4,10 +4,25 @@
 
 ### tl; dr
 
-* [fair ordering sequencing](fair_ordering_sequencing.md)
+<br>
+
+* optimistic rollup
 
 <br>
 
+----
+
+### in this dir
+
+<br>
+
+* [gmx](gmx.md)
+
+<br>
+
+---
+
 ### resources
 
-* [Transaction ordering policy](https://research.arbitrum.io/t/transaction-ordering-policy/127)
+* [transaction ordering policy](https://research.arbitrum.io/t/transaction-ordering-policy/127)
+* [fair ordering sequencing](fair_ordering_sequencing.md)