Update README.md

README.md

@@ -145,11 +145,13 @@ struct BatchCompact {
 }
 
 // A multichain compact can declare tokens and amounts to allocate from multiple chains,
-// each designated by their chainId. Any allocated tokens must designate the Multichain
-// scope. Each allocation may designate a unique arbiter for the chain in question.
-struct Allocation {
+// each designated by their chainId. Any allocated tokens on an exogenous domain (e.g. all
+// but the first segment) must designate the Multichain scope. Each segment may designate
+// a unique arbiter for the chain in question. Note that the witness data is distinct for
+// each segment, but all segments must share the same EIP-712 witness typestring.
+struct Segment {
     address arbiter; // The account tasked with verifying and submitting the claim.
-    uint256 chainId;
+    uint256 chainId; // The chainId where the tokens are located.
     uint256[2][] idsAndAmounts; // The allocated token IDs and amounts.
     // Optional witness may follow.
 }
@@ -162,7 +164,7 @@ struct MultichainCompact {
     address sponsor; // The account to source the tokens from.
     uint256 nonce; // A parameter to enforce replay protection, scoped to allocator.
     uint256 expires; // The time at which the claim expires.
-    Allocation[] allocations;
+    Segment[] segments; // Arbiter, chainId, ids & amounts, and witness for each chain.
 }
 ```