ELI5: Explain Like I'm 5

Markov operator

Okay kiddo, let me explain what a Markov operator is. You know how when you play a game, you usually have to make decisions based on what happened before? Like if you're playing hide-and-seek, you might remember where your friends have gone before and try to find them based on that.

Well, a Markov operator is like that, but for math! It's something that helps us make predictions based on what happened before. Specifically, it helps us predict the *probabilities* of different things happening next.

Think of it like this. Imagine you're playing a game where you can move up, down, left, or right. You can only move to certain squares on the game board, but you don't always move the same way every time. What a Markov operator does is take all the possible moves you could make, and figure out the probability of each one.

For example, maybe there's a 10% chance you'll move up, a 30% chance you'll move down, a 20% chance you'll move left, and a 40% chance you'll move right. We call these probabilities the "transition probabilities", because they tell us how likely it is that we'll transition from one state (where we are now) to another state (where we could be next).

Now, if we know the transition probabilities, we can use a Markov operator to figure out other things. Like, for example, if we're trying to get to a certain square on the game board, we can use the Markov operator to figure out the probability of getting there in a certain number of moves.

It might sound complicated, but it's actually a really helpful tool for predicting things in all sorts of situations - not just games! Scientists and engineers use Markov operators to predict everything from how diseases spread to how power grids will behave under certain conditions.

So, to sum up: a Markov operator is a tool that helps us predict probabilities based on what happened before. It's useful for all sorts of things, and it's kind of like playing a game where you have to think about all the different moves you might make.