Markov chains are a mathematical concept used to model a sequence of possible events in which the probability of each event depends only on the outcome of the previous event. In other words, they are stochastic processes that involve a sequence of random variables where the future state of the system only depends on its current state and not on its past history. Markov chains are widely used in various fields such as physics, biology, economics, and computer science to model the behavior of complex systems. They are particularly useful for analyzing systems that evolve over time in a probabilistic manner, such as the movement of particles in a gas, the spread of infectious diseases, or the behavior of financial markets. The study of Markov chains involves analyzing the properties of transition probabilities between different states, determining the long-term behavior of the system, and finding optimal strategies for reaching a desired state. Various mathematical techniques, such as matrix algebra, graph theory, and stochastic processes, are used to analyze and solve problems related to Markov chains.