An interesting example of Brouwer's fixed point theorem: I think the tummy button of the snowman on the girl's PJs lines up with her own tummy button.

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Apr 04, 2020, 15:31

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Apr 04, 2020, 15:31

Apr 04, 2020, 15:31

Christian Lawson-Perfect @christianp@mathstodon.xyz

Real-world analysis: for any ε>0, there is a dog δ such that δ's whiskers are within ε of my toast.

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Apr 03, 2020, 17:35

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Apr 03, 2020, 17:35

Apr 03, 2020, 17:35

Christian Lawson-Perfect @christianp@mathstodon.xyz

The toddler has started using the words 'maybe' and 'probably'. Time to inoculate her against frequentist interpretation.

b0de8de673269e9a.jpg?1585935281

**Christian Lawson-Perfect** · Apr 02, 2020, 18:18

Christian Lawson-Perfect boosted

**Gabriel Nivasch** @gnivasch@mathstodon.xyz · Apr 02, 2020, 18:18

Apr 02, 2020, 18:18

Gabriel Nivasch @gnivasch@mathstodon.xyz

In these days in which "exponential growth" has such ominous connotations, we are pleased to announce our new paper which includes fast-growing functions in a much lighter setting. Fusible numbers and Peano Arithmetic. https://arxiv.org/abs/2003.14342 . Joint work with @jeffgerickson and @alreadydone

**Christian Lawson-Perfect** · Apr 01, 2020, 14:24

Christian Lawson-Perfect boosted

**Antoine Chambert-Loir** @antoinechambertloir@mathstodon.xyz · Apr 01, 2020, 14:24

Apr 01, 2020, 14:24

Antoine Chambert-Loir @antoinechambertloir@mathstodon.xyz

How to choose socks, an April Fool's tale by Matt Baker,
https://mattbaker.blog/2020/04/01/zero-knowledge-identification-and-one-way-homomorphisms/

and an earlier version, by myself, on @ImagesDesMaths@twitter.com
https://images.math.cnrs.fr/Je-suis-daltonien-mais-je-m-en-sors.html

Happy reading, bonne lecture !

**Christian Lawson-Perfect** · Apr 01, 2020, 08:16

Christian Lawson-Perfect boosted

**St�phanie W.** @stephaniewalter@mastodon.design · Apr 01, 2020, 08:16

Apr 01, 2020, 08:16

St�phanie W. @stephaniewalter@mastodon.design

#Accessibility
A color contrast checker that offers alternatives if your color combination has not enough contrast. It would be cool to chose if you want to change background or foreground though but it's still very nice to get suggestions

https://polypane.app/color-contrast/#fg=rgb(255%2C%20255%2C%20255)&bg=rgb(254%2C%20220%2C%2042)&level=aa

0895008033b8d3e1.jpg

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Apr 01, 2020, 08:52

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Apr 01, 2020, 08:52

Apr 01, 2020, 08:52

Christian Lawson-Perfect @christianp@mathstodon.xyz

@ColinTheMathmo red looks darker for me, so no problem. Not sure if it's a problem for people with the deuteranopia (missing blue receptors)

**Christian Lawson-Perfect** · Mar 31, 2020, 21:59

Christian Lawson-Perfect boosted

**jsiehler** @jsiehler@mathstodon.xyz · Mar 31, 2020, 21:59

Mar 31, 2020, 21:59

jsiehler @jsiehler@mathstodon.xyz

Schwarz-Rot-Gelb

774d4b77a207f634.mp4?1585691947

**Christian Lawson-Perfect** · Mar 31, 2020, 22:53

Christian Lawson-Perfect boosted

**Antoine Chambert-Loir** @antoinechambertloir@mathstodon.xyz · Mar 31, 2020, 22:53

Mar 31, 2020, 22:53

Antoine Chambert-Loir @antoinechambertloir@mathstodon.xyz

RT @MathsEdIdeas@twitter.com

A little something that may help... 320 Random Acts of Maths: pocket-sized problems, teasers, curios, provocations, inspirations, etc. For downloads, inc. solutions and slides: http://bit.ly/2MkTnFM • #maths #math #MTBoS #iteachmath #mathsathome #MathsEveryoneCanAtHome

🐦🔗: https://twitter.com/MathsEdIdeas/status/1244940414156771328

02bf03af3f4fb506.jpg?1585695214

**Christian Lawson-Perfect** · Apr 01, 2020, 03:58

Christian Lawson-Perfect boosted

**Wayne Mackintosh 🇳🇿🐧** @mackiwg@mastodon.oeru.org · Apr 01, 2020, 03:58

Apr 01, 2020, 03:58

Wayne Mackintosh 🇳🇿🐧 @mackiwg@mastodon.oeru.org

OERu joins forces with COL, UNESCO (IITE) and ICDE to establish an #OER support group to assist institutions transitioning to online learning during the #COVID19 crisis. Please join our #OER4Covid support group: https://oer4covid.oeru.org/

65fcf3467aaa570f.png

**Christian Lawson-Perfect** · Mar 30, 2020, 21:44

Christian Lawson-Perfect boosted

**Henry Segerman** @henryseg@mathstodon.xyz · Mar 30, 2020, 21:44

Mar 30, 2020, 21:44

Henry Segerman @henryseg@mathstodon.xyz

A variant of the classic 15-puzzle, where the puzzle is coiled around a cylinder. Unlike the original, this version is solvable because of the extra connection between the first and sixteenth squares of the frame. YouTube: https://youtu.be/rfAEgxNEOrQ

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:15

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:15

Mar 30, 2020, 13:15

Christian Lawson-Perfect @christianp@mathstodon.xyz

@ColinTheMathmo The root of it was "how can I get my friends to show me cool bits of maths?"

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:15

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:15

Mar 30, 2020, 13:15

Christian Lawson-Perfect @christianp@mathstodon.xyz

@ColinTheMathmo did you follow the math-offs in 2019 and 2018?
A "pitch" is just an essay or a video or a paragraph about some interesting maths. Like a Big MathsJam talk in a blog post.
The competition element is just to provoke interest - doesn't mean anything, really. Readers will be asked to vote for the pitch that made them go "Aha!" the loudest.

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:11

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:11

Mar 30, 2020, 13:11

Christian Lawson-Perfect @christianp@mathstodon.xyz

@ColinTheMathmo it would make a good entry in the lock-down math-off 😉

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:10

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:10

Mar 30, 2020, 13:10

Christian Lawson-Perfect @christianp@mathstodon.xyz

@ColinTheMathmo cool!
A technical note: the camera seems to keep adjusting focus. There's an app called Open Camera (https://f-droid.org/en/packages/net.sourceforge.opencamera/) that lets you lock the focus while recording

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:04

**Christian Lawson-Perfect** @christianp@mathstodon.xyz · Mar 30, 2020, 13:04

Mar 30, 2020, 13:04

Christian Lawson-Perfect @christianp@mathstodon.xyz

@ColinTheMathmo yep!

**Christian Lawson-Perfect** · Mar 29, 2020, 17:55

Christian Lawson-Perfect boosted

**jsiehler** @jsiehler@mathstodon.xyz · Mar 29, 2020, 17:55

Mar 29, 2020, 17:55

jsiehler @jsiehler@mathstodon.xyz

A problem of mine appeared in the lastest Mathematics Magazine:
Suppose \(\pi\) is a permutation of \(\{1,2,\ldots,2m\}\). Consider the (possibly empty) subsequence of \(\pi(m+1),\pi(m+2),\ldots,\pi(2m)\) consisting of only those values which exceed \(\max\{\pi(1),\ldots,\pi(m)\}\).

Let \(P(m)\) denote the probability that this subsequence never decreases, when \(\pi\) is a randomly chosen permutation of \(\{1,2,\ldots,2m\}\). Evaluate the limit of \(P(m)\) as \(m\to\infty\).