how does proof of work prevent double spending
Double-spending The cryptocurrency bitcoin implemented a solution in early 2009. It uses a cryptographic protocol called a proof-of-work system to avoid the need for a trusted third party to validate transactions. Instead, transactions are recorded in a public ledger called a blockchain. A transaction is considered valid when it is included in the blockchain that contains the most amount of computational work. This makes double-spending more difficult as the size of the overall network grows.[5] Other cryptocurrencies also have similar features.