My first toot about this contained an example using pictures of humans. A couple of people rightly pointed out that that could lead to some unwanted reactions to the prompt, which I hadn't realised. I've deleted it, so here's another attempt

I've made a tool for making "Which One Doesn't Belong?" pictures.

You can put text or pictures in each square, and change the colours of the background and text.

Today I've made my first contribution to MathJax in almost three years, adding the ability to specify a 'nonce' value for the stylesheets it creates, to comply with the site's Content Security Policy.

I've got an issue on the MathJax issue tracker explaining in a bit more detail: https://github.com/mathjax/MathJax/issues/2665

In particular, this makes MathJax work in mastodon again.

@christianp I remember a conference talk on the proof that braid groups are linear. The presenter explained that his proof would use "forks and noodles," and went on to clarify that "noodles" are embedded arcs that represent certain cohomology classes, and "forks" are, "...um, what you use to detect noodles."

@christianp Because then all the physicists like me would confuse it with "six-bar", which is six over two pi

@EdPeggJr hi! Welcome to mathstodon!

I came across this nice integerological fact:

Define \(\operatorname{ord}_p(n)\) to be the power of \(p\) in the prime factorisation of \(n\).

Then

\[ \sum_{k=1}^n\gcd(n,k) = \prod_{p|n} \left(1+\left(1-\frac{1}{p}\right) \cdot \operatorname{ord}_p(n)\right) \]

I don't know why you'd want to do this, and all the references I've found to it talk about it as a special case of some more general identities, but for some reason it appealed to me.

victorians: demonstrate refined sensibilities by falling gravely ill when presented with the wrong cutlery

me: six-week catatonic state brought on by overfull hbox

- Homepage
- http://somethingorotherwhatever.com

- Location
- Newcastle upon Tyne, UK

- Pronouns
- he/him

- Favourite number
- 3435

Admin

Mathematician, koala fan, mathstodon.xyz admin,

⅓ of https://aperiodical.com. He/him

Joined Apr 2017