How do the SCDO Mainnet and the subchain connect in terms of Consensus?

Answer: The SCDO Mainnet and the Stem Sub-chain have an independent yet interconnected relationship in terms of Consensus. The Mainnet adopts ZPoW Consensus, maintained by global miners, which ensures a very high level of security and data immutability.
Each subchain can choose a consensus algorithm suitable for itself, such as PBFT (Practical Byzantine Fault Tolerance) or PoS, to achieve consensus within the subchain.
This means that the block production of the subchain is determined by the nodes of the subchain according to the subchain Consensus, and subchain transactions are not directly verified by mainchain miners.
Nevertheless, the mainchain supervises the sidechains through smart contracts: sidechains are required to periodically submit their state hashes to the mainchain, which is equivalent to filing the latest state of the sidechains on the mainchain.
The main chain miners will package this hash into a main chain block, making it irreversibly recorded on the entire network. In addition, in case of disputes, anyone can submit subchain transaction data to the main chain for verification (challenge), which will be judged for correctness by the mainnet miners.
Therefore, the mainchain consensus provides ultimate security endorsement for the subchain: even if the internal consensus of a certain subchain may be weak (for example, PoS is controlled by a minority), attackers cannot tamper with its final state and escape the supervision of the mainchain.
It can be said that the SCDO Mainnet and side chains form a master-slave collaborative consensus system: the mainnet maintains the global trust root, while the side chains operate independently and efficiently, but must periodically "report" to the mainnet to earn the trust of the entire network.