Consider the algorithm "M(x): if x<0 return -x, else return M(x-M(x-1))/2". This algorithm terminates for all real x, though this is not so easy to prove. In fact, Peano Arithmetic cannot prove the statement "M(x) terminates for all natural x". Paper to come! Joint work with @jeffgerickson and @alreadydone

@bremner Me, a Mathematica user for decades: Why yes, (#^%%)! & /@ %%% seems like a perfectly reasonable thing to write, why do you ask?

...it also works with random points

These are the self-intersecting onions @jeffgerickson was mentioning

How to peel self-intersecting onions: arxiv.org/abs/1909.00263

A Mastodon instance for maths people. The kind of people who make $$\pi z^2 \times a$$ jokes. Use $$ and $$ for inline LaTeX, and $ and $ for display mode.