According to Wu Shuo, Rooch Network developer jolestar analyzed the definition of Bitcoin L2 and believed that it should be analyzed from both technical and ecological perspectives, and advocated an inclusive perspective of L2. Defined from a technical perspective, the key is to make L2 clearly different from L1 and centralized solutions. There are two points: L2 does not create new block space and L2 needs to use L1 to achieve data availability and security. Defined from an ecological perspective, the focus is on how L2 utilizes or inherits the capabilities provided by L1. The inheritable and scalable directions include BTC assets, Bitcoin block space, the programmability of the Bitcoin network, and the status of Bitcoin; extended Bitcoin solutions include Bridge+ Programmable environment, extending a smart contract layer on Bitcoin, Indexer mode Offchain computing and Stackable L2 (the above solutions can all cooperate with each other through the combination mode).

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