I think I’ve just been doing that all along! And 💯

Where’s the picture please?!

Thanks to @mjsimpson.bsky.social and @profruthbaker.bsky.social for the excellent collaboration, and to the journal editors for the invitation to contribute.

We show how these process often give rise to nonlinear terms in the governing equations. With plenty of worked examples we hope this will be a useful resource for modellers and researchers starting out in this area.

Classical random walk theory applies to movement models where there are no interactions between individuals. In this paper, we cover extensions of his theory to situations where individuals interact in specific ways, e.g. crowding effects or competition.