ELI5: Explain Like I'm 5

Stochastic partial differential equations

Okay, kiddo, imagine you're playing with a coloring book and you've been given a paintbrush with different colors. You start coloring and staying inside the lines, but you notice that your hand shakes a little bit making your color stray from the lines.

Similarly, in the world of math and science, scientists are interested in modeling things that are affected by random events or variability. These random events can come from various sources like weather patterns, the movements of individual particles, or just the unpredictable nature of certain systems. That’s where stochastic calculus comes in. It’s a branch of calculus that deals with probability and random events.

Stochastic partial differential equations (SPDEs) are just like the coloring book example except this time, it’s a little more complicated. Imagine taking a big picture and dividing it into tiny, tiny pieces - this is called discretization. Now, let’s imagine that each little piece (or pixel) is behaving differently because of the randomness of the system. For example, a drop of water falling onto a sponge will spread out in all directions, but not exactly the same way each time. It’s like putting a drop of food coloring into a glass of water. Each time you do it, the colors will blend differently.

So, SPDEs help scientists to model these complicated systems by capturing the random behavior and quantifying how it affects the overall behavior of the system. This allows scientists to make predictions and gain a better understanding of the world around us.

In short, stochastic partial differential equations is a fancy way of dealing with randomness and modeling complex systems in a way that we can better understand!