Plasma = Layer2(OPU, ZkR)
Public.icon
In the Plasma plan, a way to scale without losing the characteristics of Ethereum was proposed. The idea of using L1 as a court was similar, but it was amazing to propose something completely different depending on the application destination.
https://gyazo.com/77b935a52cd2511f48db1f0fa2d60e63
In other words, the problem was that it was possible to justify fraudulent assets by winning the Exit Game using the worst data accessibility problem, but this was solved by introducing a mechanism to reject all L2 transactions that were mistakenly put on-chain to eliminate the data accessibility problem (i1). And the later Exit Game was eliminated by refusing to update to an invalid Merkle Root with zero-knowledge proof or proving fraud (fraud proof) if there was any wrongdoing within 7 days. The former is called zkRollup and the latter is called Optimistic Rollup. Rollup refers to the method described in (i1). Layer2 aims to reduce Ethereum transaction fees and improve transactions.
Layer2 literally means "second layer". So what is the "first layer"? It is the Ethereum blockchain.
Layer2 (second layer) is stacked on top of the Ethereum blockchain (first layer).
The idea is that it is difficult to do all the processing on Ethereum (on-chain), so some of the processing can be done off Ethereum (off-chain).
Types of Layer2
dYdX, which utilizes the technology of StarkEX, is one of the DEXs that are supported. It is more convenient than Zk-Rollup, which cannot use EVM. Ways to address the scaling issue on Ethereum's Main Chain include separating computation and data storage through the use of a Layer 2 chain separate from the Mainnet to solve scaling issues.
However, I think Zk-Rollup will win in the long term. The reason is that _ Optimistic Rollup has the disadvantage of not being able to withdraw for 7 days, which is solved by ZK-Rollup.