Reorg collators page

docs/learn/learn-collator.md

@@ -4,74 +4,33 @@ description: Understand the role of collators in Polkadot, including block produ
 ---
 
 !!!info
-    This page provides a general overview of the role of collators' in the Polkadot ecosystem. For more detailed information you can read the [Parachain Protocol Overview](./learn-parachains-protocol.md).
+    This page provides a general overview of the role of collators in the Polkadot ecosystem. For more detailed information, read the [Parachain Protocol Overview](./learn-parachains-protocol.md).
 
 ## Collators' Role
 
-Collators maintain parachains by collecting parachain transactions from users and producing state
-transition proofs for relay chain validators. In other words, collators aggregate parachain transactions into parachain block candidates and produce state transition
-proofs (Proof-of-Validity, PoV) for validators.
-
-Collators maintain a full node for the relay chain and a full node for their particular parachain;
-meaning they retain all necessary information to be able to author new blocks and execute
-transactions in much the same way as miners do on PoW blockchains. Under normal circumstances, they
-will collate and execute transactions to create an unsealed block and provide it, together with a
-PoV, to one or more validators responsible for proposing a parachain block.
-
-Collators are similar to validators on any other blockchain but they do not need to provide security
-guarantees because the relay chain provides those. If a parachain block is invalid, it will get
-rejected by validators. The validators are required to check the validity of submitted candidates,
-followed by issuing and collecting statements about the validity of candidates to other validators.
-This process is known as **candidate backing**. Validators receive an arbitrary number of parachain
-candidates with associated PoV from untrusted collators. A candidate is considered _backable_ when
-at least 2/3 of all assigned validators have issued a valid statement about that candidate.
+### Rollup Maintainers
 
-The validator must successfully verify the following conditions in the following order:
-
-1. The candidate does not exceed any parameters in the persisted validation data.
+Collators maintain rollup chains (parachains) by collecting user transactions and producing state transition proofs for Polkadot's validators. In other words, collators aggregate transactions into parachain block candidates and produce state transition
+proofs (Proof-of-Validity, PoV) for validators.
 
-2. The signature of the collator is valid.
+Collators maintain a full node for the relay chain and a full node for their particular parachain, meaning they retain all necessary information to author new parablocks and execute transactions like miners do on PoW blockchains. Under normal circumstances, they
+will collate and execute transactions to create an unsealed block and provide it with a PoV to one or more validators on a Polkadot core.
 
-3. Validate the candidate by executing the parachain Runtime.
+Collators are similar to validators on any other blockchain. Still, they do not need to provide security guarantees because the relay chain provides those as a service via [the ELVES protocol](https://eprint.iacr.org/2024/961). If a parachain block is invalid, validators will reject it.
 
-Once a candidate meets a specified criteria for inclusion, the selected relay chain block author
-then chooses any of the backable candidates for each parachain and includes those into the relay
-chain block. We say the candidate blocks are _backed_.
+### Rollup Liveness and Censorship
 
-The assumption that having more collators is better or more secure is not correct. On the contrary,
-too many collators may slow down the network. The only nefarious power collators have is transaction
-censorship. To prevent censorship, a parachain only needs to ensure that there are some neutral
-collators - but not necessarily a majority. Theoretically, the censorship problem is solved by
-having just one honest collator.
+Rollup safety (i.e., the insurance that invalid transactions are not included on the rollup) is achieved through validators on the relay chain implementing the ELVES protocol. But the onus of liveness (i.e., new blocks are eventually produced) and censorship resistance on the rollup is the responsibility of the collators. Hence, a sufficiently [decentralised collator](../general/web3-and-polkadot.md#decentralization) set ensures liveness and mitigates censorship resistance. Theoretically, a single honest collator can ensure liveness but with reduced throughput.
 
-## XCM
+### Cross-consensus Messaging
 
 Collators are a key element of the [XCM (Cross-Consensus Message Passing Format)](learn-xcm.md). By
 being full nodes of the relay chain, they are all aware of each other as peers. This makes it
 possible for them to send messages from parachain A to parachain B.
 
-## Taking the Case for One Parachain
-
-A start of a new block candidate is initiated with a block creation time. The collator aggregates
-all new transactions at the end of the process. When doing so, the collator signs the _parachain
-block candidate_ and produces state transition proofs (Proof-of-Validity, PoV), which are a summary
-of the final account balances caused by the transactions in the candidate block. The collator sends
-the candidate block and PoV to the parachain validators, so-called para-validators. The
-para-validators verify the transactions within the parachain block candidate. Upon verification, and
-if all is well, the candidate becomes _backable_ and a para-validator shares the candidate block
-with the relay chain.
-
-![parachain candidate block diagram](../assets/polkadot-consensus-example-1.png)
-
-The validators on the relay chain will try to reach a consensus on the block candidate. Upon
-reaching consensus, the now validated block candidate is shared with the validators and collators,
-and the process repeats for new transactions. A collator cannot continue building blocks on a
-parachain until the block candidate they proposed to the relay chain validators have been validated.
-A block is produced every 6 seconds.
-
 ## Collators in the Wild
 
-Blockchains that are built using Substrate are unable to hook onto the relay chain on their own. The
+Blockchains built using Substrate cannot hook onto the relay chain independently. The
 Parity team built the
 [Cumulus library](https://github.com/paritytech/polkadot-sdk/tree/master/cumulus/) to address this.
 Collators are being used on the [Paseo](https://docs.polkadot.com/develop/parachains/testing/) testnet,
@@ -83,6 +42,4 @@ Rust documentation. More information can be found under the
 ## Guides and Tools
 
 - [Tutorial covering Cumulus and Collators](https://docs.polkadot.com/develop/toolkit/parachains/spawn-chains/zombienet/get-started/)
-- [Paseo testnet guide](https://docs.polkadot.com/develop/parachains/testing/)
-- [polkadot-launch](https://github.com/shawntabrizi/polkadot-launch) - a tool to quickly spin up a
-  local Polkadot testnet based on some parameters like number of parachains, collator setup, etc.
+- [Paseo testnet guide](https://docs.polkadot.com/develop/parachains/testing/)