Dan Marsden

Revised draft paper with Ralf Hinze, with many improvements. Formal monad theory, calculational reasoning with string diagrams, and lots of colourful pictures. Now featuring this funny robot like character. On my website as too much for the arXiv. stringdiagram.com/wp-content…

Back to drawing string diagrams, this time related to commutative squares of adjunctions. Just two iterations of a proof step that intuitively slides a twist around a bend. Also evidence I seem to be turning into some sort of retro wallpaper designer.

An enjoyable day pushing to get our second string diagrams book finished. Really just drawing colourful pictures in the garden.

Back to drawing string diagrams again. This time somewhat abusing the notation, favouring conveying the right intuition to the reader over strict adherence to rules.

Colourful string diagrammatic proof to start the week, involving monads, Kleisli laws, and composition of 2-cells between them.

Enjoying drawing some different renderings of the same string diagram, to show how they evolve as you better understand the information you wish to convey. With a lot of topological freedom, and judicious use of identity vertices, there's a lot of scope for artistic expression.

More string diagram art work in formal monad theory. I'm intrigued by the fundamental role the white identity vertices are playing. It's also interesting to contrast the first 2 topological steps that slide and bend stuff with the more drastic last step that changes connectivity

As I often post pretty string diagrams, I though I'd show something more practical - a real whiteboard proof, including distributive laws, explicit identities, adjunctions and monads. In small is a poor first go at one of the drawings - my first choices aren't always the best!

I've been having fun drawing string diagrams again, and have learned a few new tricks. I've upgrade my how to draw document with what I've learned: stringdiagramcom.files.wordp… Including path reuse, better layering, easier alignment, and the experimental shadowing effect below

I'm not sure how I didn't know this before, but Jacob Neumann, a PhD student in Nottingham FP lab has been doing very cool introductory videos to homotopy type theory, with excellent explanations. Now feeling I'll have to up my own expository game. youtube.com/watch?v=Pu16iodE…