Regarding the problem of scalability of Blockchain as a decentralized and cryptographically secure database is one of the new technologies; that will undoubtedly have a great impact on the future of the digital world. But with an increasing impact comes an increasing number of users; and there a great problem occurs.

Most of the currently known blocking networks are not made for many users; and I mean many users. Let’s take a look at the most famous Blockchain system, Bitcoin. The size of a block, which determines the amount of data that can be stored, is limited to 1MB.

The cryptocurrencies, the data stored in cryptocurrency block chains; They are transaction data. A block has to be generated and then validated by the network, and this takes time. Therefore, there is only a limited number of transactions ; that can be done for a certain period of time.

But as all this technology attracts more and more participants; the time to handle such transactions increases. This is called the problem of scalability; a solution had to be found, and the IOTA did find it.

#### IOTA and Tangle

The IOTA foundation had a pretty good idea, the so-called Tangle system. Therefore, they used their knowledge of a subject of mathematics called Theory of Graphics.

We have blocks of information; each block contains certain data and is connected to the previous block through a hash value calculated cryptographically.

What can be understood is that the Acíclico Graph Directed in mathematics; For the purpose of understanding all this it is sufficient to know that a graph is only a set of vertices and edges. Directed means that the edge, which connects two vertices; it goes from one vertex to the other.

In the Tangle system, each transaction is represented by a vertex; this means that if someone is in the process of transferring some funds from the IOTA , it generates a transaction; which then becomes a vertex of the graph.

The key now is that each transaction has to approve at least two other transactions; In terms of mathematics this means that each vertex has to be connected by directing the edges towards at least two other vertices. It is said that a transaction is indirectly approved by another transaction; if there is a connection between these two transactions with at least one transaction between them.

Therefore, instead of storing transactions in blocks of limited size; Each transaction lives on its own and has to approve other transactions. With this method, the number of transactions; which can be handled in a certain period of time, increases with the number of transactions!