Quoted Shape: The Hidden Geometry of Information, Biology, Strategy, Democracy, and Everything Else by Jordan Ellenberg (Penguin Press)
You don’t make a bagel by first baking a bialy and then punching out the center. No—you roll out a snake of dough and join the ends together to form the bagel. If you denied that a bagel has a hole, you’d be laughed out of New York City, Montreal, and any self-respecting deli worldwide. I consider this final.
Not exactly a QED sort of proof, but I’ll take it as an axiom. 🙂

Differential Topology—Two quarter sequence at UCLA Extension for Fall/Winter 2021

It hasn’t been announced officially in the UCLA Extension catalog, but Dr. Mike Miller’s anticipated course topic for Fall 2021 is differential topology. The anticipated recommended text is Differential Topology: An Introduction by David B. Gauld (M. Dekker, 1982 or Dover, 1996 (reprint)).

The offering is naturally dependent on potential public health measures in September, which may also create a class limit on the number of attendees, so be sure to register as soon as it’s announced. For those who are interested in mathematics, but have never attended any of Dr. Miller’s lectures, I’ve previously written some details about his stye of presentation, prerequisites (usually very minimal despite the advanced level of the topics), and other details.

A few of us have already planned weekly Thursday night topology study sessions through the end of Spring and into Summer for those interested in attending. Just leave a comment with your contact information and I’ll be in touch with details.

I hope to see everyone in the fall.

An Euclidean Declaration

So far, my favorite part of Jordan Ellenberg‘s new book Shape: The Hidden Geometry of Information, Biology, Strategy, Democracy, and Everything Else is this footnoted observation:

“we hold these truths to be self-evident” wasn’t Jefferson’s line; his first draft of the Declaration has “we hold these truths to be sacred & undeniable.” It was Ben Franklin who scratched out those words and wrote “self-evident” instead, making the document a little less biblical, a little more Euclidean.

Evie (taunting me to tuck her in before she gets to 15): …, 9-Mississippi, 10-Mississippi, 11-Mississippi, …

Me: We don’t Mississippi in this house! Maybe we should Tennessee since that’s where Grandma and Grandpa live?

Evie: I’ve Mississippi’ed since I was three.

Me: Maybe since we’re Welsh we should Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch? You know: 1-Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch, 2-Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch, …

Together: 3-Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch…

Evie (interrupting): Wait, what number are we on now???

Bookmarked The Mountains of Pi by Richard Preston (The New Yorker)
The Chudnovsky brothers yearned to probe the mystery of pi, so they built their own supercomputer out of mail-order parts.
I know I’ve read this before. This is a good reminder to re-read it occasionally.

John Keilman on Twitter: “@rachsyme This one. It makes math make sense in a way nothing else has. https://t.co/VWST1TiQAZ”

Read Longtime philosophy Professor Stephen Barker dies at 92 (The Hub)
He was named professor emeritus after teaching in the Department of Philosophy for nearly four decades
I was thinking about logic a bit this evening and looked up an old professor. Saddened to hear he’s passed away.
Listened to The World, Remade from On the Media | WNYC Studios

How the pandemic has shaped our future: from the built environment, to the way we work, to the way we learn.

With vaccinations underway, we’re edging closer and closer to the end of the pandemic. This week, On The Media looks at how the pandemic has shaped what’s possible for the future — from the built environment to the way we work to the way we learn.

1. Sam Kling [@SamKling2], American Council of Learned Societies public fellow, on whether cities like New York were bound to become hubs for disease. Listen.

2. Vanessa Chang [@vxchang], lecturer at California College of the Arts, explains how pandemics of the past have been instrumental in shaping architecture; Mik Scarlet [@MikScarlet] delineates the social model of disability; and Sara Hendren [@ablerism], author of What Can A Body Do?: How We Meet the Built World, describes how the wisdom of people with disabilities can inform the redesign our post-pandemic world. Listen.

3. OTM reporter Micah Loewinger [@micahloewinger] tells the story of how distance learning saved his friend's life. Listen.

Read Postdoctoral position in HoTT at Johns Hopkins University by Emily RiehlEmily Riehl (Homotopy Type Theory)
The Department of Mathematics at Johns Hopkins University solicits applications for one two-year postdoctoral fellowship beginning Summer 2021 (with some flexibility in the start and end dates). Th…
Bookmarked The ergodicity problem in economics by Ole Peters (Nature Physics volume 15, pages1216–1221(2019))
The ergodic hypothesis is a key analytical device of equilibrium statistical mechanics. It underlies the assumption that the time average and the expectation value of an observable are the same. Where it is valid, dynamical descriptions can often be replaced with much simpler probabilistic ones — time is essentially eliminated from the models. The conditions for validity are restrictive, even more so for non-equilibrium systems. Economics typically deals with systems far from equilibrium — specifically with models of growth. It may therefore come as a surprise to learn that the prevailing formulations of economic theory — expected utility theory and its descendants — make an indiscriminate assumption of ergodicity. This is largely because foundational concepts to do with risk and randomness originated in seventeenth-century economics, predating by some 200 years the concept of ergodicity, which arose in nineteenth-century physics. In this Perspective, I argue that by carefully addressing the question of ergodicity, many puzzles besetting the current economic formalism are resolved in a natural and empirically testable way.
Kevin Marks retweet () of 
Simon Wardley @swardley in Simon Wardley on Twitter: “Anyway, this is a fabulous paper – The ergodicity problem in economics – https://t.co/fzS3toWvT5 … well worth the read.” / Twitter ()
Annotated The ergodicity problem in economics by Ole Peters (Nature Physics volume 15, pages1216–1221(2019))
Ergodic theory is a forbiddingly technical branch of mathematics. 
It’s supremely sad that a paper in Nature should “math shame” ergodic theory this way. What the hell is going on?
Read - Want to Read: Shape: The Hidden Geometry of Information, Biology, Strategy, Democracy, and Everything Else by Jordan Ellenberg (Penguin Press)
From the New York Times-bestselling author of How Not to Be Wrong, himself a world-class geometer, a far-ranging exploration of the power of geometry, which turns out to help us think better about practically everything
How should a democracy choose its representatives? How can you stop a pandemic from sweeping the world? How do computers learn to play chess, and why is learning chess so much easier for them than learning to read a sentence? Can ancient Greek proportions predict the stock market? (Sorry, no.) What should your kids learn in school if they really want to learn to think? All these are questions about geometry.
For real. If you're like most people, geometry is a sterile and dimly-remembered exercise you gladly left behind in the dust of 9th grade, along with your braces and active romantic interest in pop singers. If you recall any of it, it's plodding through a series of miniscule steps, only to prove some fact about triangles that was obvious to you in the first place. That's not geometry. OK, it is geometry, but only a tiny part, a border section that has as much to do with geometry in all its flush modern richness as conjugating a verb has to do with a great novel.
Shape reveals the geometry underneath some of the most important scientific, political, and philosophical problems we face. Geometry asks: where are things? Which things are near each other? How can you get from one thing to another thing? Those are important questions. The word geometry, from the Greek, has the rather grand meaning of measuring the world. If anything, that's an undersell. Geometry doesn't just measure the world - it explains it. Shape shows us how.
Bookmarked Ergodicity: Definition, Examples, And Implications, As Simple As Possible (Gumroad)
Some reviews of Luca's previous books"This book is like a magnificent suspension bridge, linking the science of the human brain to the practical craft of applying it in everyday life. I loved it." – Rory Sutherland, Ogilvy's Vice Chairman“A SUPERB book […] by one of the profound thinkers in our field [behavioral economics].” – Michal G. BartlettWhat's ergodicity, and why it matters?"The Most Important Property to Understand in Probability, in Life, in Anything." – Nassim Nicholas Taleb on ergodicity."I think the most under-rated idea is ergodicity." – David Perell, author.Is ergodicity the most important concept in decision-making and behavioral sciences? (Yes.)Is it relevant for you in your daily life? (Yes.)Is it possible to explain it so simply that a grandma or a high-schooler can understand it? (Yes.)Even if they know nothing about maths? (Yes.)That's because ergodicity is an important idea with so many practical applications. Sadly, most books describe it in a very technical way, making it inaccessible to most people.In this short book, 6-times author Luca Dellanna describes ergodicity as simply as possible. You will read stories about how not knowing about it destroyed his cousin’s career as a skier, or how misunderstanding it caused additional deaths during the pandemic. You will learn how to spot situations in which ergodicity matters and the three strategies to react appropriately.The book is approximately 166 pages long, of which 143 are pure content and the rest tables of content, etc.This page sells the eBook / Kindle version. Around mid-November, the paperback version will become available on Amazon and in selected stores (e.g., most Barnes & Noble).Who is this book for?This book is for readers interested in growing themselves, their career, or their business, and who want to learn about ergodicity and its practical applications without having to understand its mathematical foundation. No mathematical knowledge is required, only a high-school level understanding of English.Readers who want to master the theory and mathematical foundation of ergodicity are better off reading a more formal manuscript. This book is not a substitute for it, but a complement.You might also be interested in my second Roam book, on management (link).About the authorLuca Dellanna is the author of 7 books. He is a researcher in complexity science and emergent behaviors, and an operational excellence consultant. He spoke at Nudgestock and regularly teaches management workshops and risk management courses.His personal website is Luca-Dellanna.com and his Twitter is @DellAnnaLuca.What you will getBy purchasing this book, you will receive all of the following:PDF version.ePub version (compatible with Apple Books & other eBook readers).mobi version (Kindle)Moreover, you will get added to my mailing list, where I frequently publish essays that do not make it into books.The Roam versionThis book is also available as a Roam Research graph.Roam is a website that shows content in an interconnected way, a bit like Wikipedia. Reading the book this way will allow you to go back and forth content at your pace and following your interests."Ten minutes in, and I'm already questioning whether I'll want to read another non-fiction book *not* published in Roam format. How fascinating and so very valuable. Thank you Luca Dellanna" – Conor M. Ogle (link)Important: reading the Roam version requires a pre-existing Roam subscription, which is not included in this bundle.If you purchase the Roam version, you will receive the eBook in 3 formats (PDF, Kindle, and ePub) and the Roam version (as an editable .json export of the book) and a document suggesting how to import the Roam book and use it and the option to email me to request access to a live, read-only version of the book.Patron's supportThank you very much for your support, it helps me spending more time on my research.I will also add your name as a Patron in the acknowledgment section of the future editions of the book.Some more reviews of Luca's books“Luca’s book was so helpful to my work. Opened my eyes up to some more reasons why change is so hard.” – Chris Murman"A thoughtfully written book in very straightforward language." – A.L. PeeveyYou can find more reviews on the pages of my other books, such as this one.
This could be interesting as an overview to recommend
Liked a tweet (Twitter)
This, but also and specifically for mathematics! We need to normalize the idea that math is easy.