# Information theory

## Information theory :

Information theory is a branch of applied mathematics and electrical engineering that deals with the study of the transmission, storage, and processing of information. It was developed in the 1940s by Claude Shannon, and its fundamental concepts have had a major impact on the development of modern communications and computer systems.
At its core, information theory is concerned with the quantification of information. This is done using the concept of entropy, which is a measure of the uncertainty or randomness of a system. For example, if we have a coin that we know is fair, the entropy of the system is low because we know with certainty what the outcome of a coin flip will be. However, if we have a coin that we don’t know anything about, the entropy of the system is high because we have no information about the outcome of a coin flip.
Another important concept in information theory is the idea of redundancy. Redundancy is the repetition of information in a message, and it is used to help ensure that the message is transmitted accurately. For example, if we send the message “hello” over a noisy channel, there is a chance that some of the letters will be garbled or lost. However, if we repeat the message multiple times, it becomes much less likely that the entire message will be lost, because there is a higher chance that at least one of the repeated versions will be transmitted accurately.
These two concepts, entropy and redundancy, are essential for understanding how information is transmitted and processed. In order to transmit a message accurately, we need to encode the message in such a way that it has low entropy (so that it is not random) and high redundancy (so that it is not easily lost or garbled). This is done using various encoding schemes, such as error-correcting codes, which are designed to add redundancy to a message in a controlled and efficient way.
In summary, information theory is the study of the transmission, storage, and processing of information. It is concerned with quantifying information using the concepts of entropy and redundancy, and with using these concepts to design efficient and reliable communication systems.