Brief description of the bridge
Across can be used to quickly transfer tokens from an L2 to Ethereum rather than waiting for the L2's slower native settlement to complete. This is accomplished by utilizing Across liquidity pools to facilitate transfers and requiring users to pay a fee to liquidity providers for using their capital.
What is Arbitrum?
Arbitrum is a type of technology known as an optimistic rollup. It allows Ethereum smart contracts to scale by passing messages between smart contracts on the Ethereum main chain and those on the Arbitrum second layer chain. Much of the transaction processing is completed on the second layer and the results of this are recorded on the main chain drastically improving speed and efficiency.https://arbitrum.io/
What is Optimism?
Optimistic Ethereum is an EVM compatible Optimistic Rollup chain. It's designed to be fast, simple, and secure. The Optimistic Ethereum network lets you send transactions, similar to Ethereum, but with two important advantages: *Near-instant transaction finality. You know almost immediately if your transaction took place or not. *Much lower transaction fees. Typically between a 1% and 10% of of the cost on L1. *Decentralization. All transactions are posted to L1 Ethereum, inheriting the strong security guarantees of Ethereumhttps://www.optimism.io/
What is Ethereum?
Ethereum is both a blockchain network, an application platform, and a full-fledged programming language. The goal of the project is to create and publish distributed applications that do not require third party trust.https://ethereum.org/en/