Update vac/raw/decentralized-messaging-ethereum.md

Co-authored-by: Ekaterina Broslavskaya <[email protected]>

vac/raw/decentralized-messaging-ethereum.md

@@ -138,7 +138,7 @@ which consist of 3 algorithms: `2SM-Init`, `2SM-Send` and `2SM-Receive`.
 ##### 2SM-Init
 This function takes two IDs as inputs: 
 `ID1` representing the local user and `ID2` representing the other party. 
-It returns an initial protocol state sigma`.
+It returns an initial protocol state `sigma`.
 The 2SM protocol relies on a Public Key Infrastructure (PKI) or 
 a key server to map these IDs to their corresponding public keys. 
 In practice, the PKI should incorporate ephemeral prekeys.