Dag: directed acyclic graph, which means "directed acyclic graph" in Chinese. Directed acyclic graph is a way to store data. "Directed" means that all data are stored in the same direction; "Acyclic" means that there is no cycle between data structures. Like a scarf made of wool, it can be knitted all the time.

why do you want to connect lines and mark arrows? Because every time a user initiates a transaction, he must verify the previous two transactions. It's like letting an orphan choose his own adoptive parents. DAG is an orphan's world. Every transaction is born an orphan, but adoptive parents can't randomly choose. They must be rooted in Miao Hong, otherwise orphans themselves will not be elected as parents by the next generation. Not being chosen means disappearing from now on. If a transaction is not verified by later exchanges, it will become a real orphan and lose its legitimacy in the books.

DAG is a data storage structure, which has been used for more than 3 years since it was invented, and there is no problem in itself. But the difference between it and blockchain is that DAG has no traditional knowledge of * * *, and the credibility of each transaction depends on the number of people who believe in the transaction. Therefore, the core problem of using DAG technology is how to protect the agreement reached by the whole network.