Maintainer: The value of the maintainer is to update the status of the Light-client deployed on the target chain so that the verification network can run smoothly. When the maintainer updates the Light-client, a transaction must be written on-chain, resulting in a gas fee payment. Because of this, MAP Protocol's economic model has designed a portion separately to incentivize and compensate Maintainers. Running as a maintainer requires computation power, sufficient fund flow to prepay the gas fees with the target chain's token, and staking of $MAPO.
Light clients of connected blockchains on MAP Relay Chain and light clients of MAP Relay Chain on connected blockchains needs to keep up with the growth of the corresponding blockchains. This is the Maintainers’ responsibility. Maintainers in MAP protocol continuously monitor the blockchain growth of MAP Relay Chain as well as all the connected blockchains. New block headers of MAP Relay Chain are submitted to all connected blockchains to keep the light client of MAP Relay Chain updated. Meanwhile, new block headers of all connected blockchains are submitted to MAP Relay Chain to update various light clients living on MAP Relay Chain. In this way, MAP Relay Chain and each connected blockchain are aware of the most recent state of each other, laid the foundation for cross-chain message verification.
After correctly set up, each light client can verify newer block headers according to its internal state as well as the rules coded in the contract, so that dishonest Maintainers won’t be able to trick the light clients to accept invalid block headers. Or in other worlds, the security of MAP protocol does not rely on trusted maintainers. As long as the light client is correctly initialized and the implementation correctly follows the corresponding blockchain’s consensus protocol, the correctness of the light client is guaranteed cryptographically. As submitting transactions to blockchains would consumes gas, all Maintainers are rewarded with MAP tokens according to the useful work they have accomplished, e.g., the number of effective block headers submitted.