“But as much as I’ve thought about networks over the years, I didn’t appreciate (until very recently) the importance of simple diffusion.

This is our topic for today: the way things move and spread, somewhat chaotically, across a network. Some examples to whet the appetite:

• Infectious diseases jumping from host to host within a population
• Memes spreading across a follower graph on social media
• A wildfire breaking out across a landscape
• Ideas and practices diffusing through a culture
• Neutrons cascading through a hunk of enriched uranium”