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Justin Lanier

@jlanier.bsky.social

171 Followers  |  82 Following  |  97 Posts  |  Joined: 12.09.2024  |  2.4402

Latest posts by jlanier.bsky.social on Bluesky

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Yesterday I spent a fascinating morning talking maths with a group of GPs. All professions require some level of numeracy, but doctors face particular challenges when communicating mathematical ideas.
I've written up a short blog: robeastaway.com/blog/gp-maths

31.07.2025 19:50 β€” πŸ‘ 23    πŸ” 9    πŸ’¬ 3    πŸ“Œ 1

....and nickel...

29.07.2025 20:51 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

You are almostβ€”but not quiteβ€”off the grid. πŸ˜„ Hope you are having a nice getaway!

28.07.2025 20:23 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

aluminum

27.07.2025 21:22 β€” πŸ‘ 3    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
Wolfram Demonstrations Project Explore thousands of free applications across science, mathematics, engineering, technology, business, art, finance, social sciences, and more.

Make more yourself at this link: demonstrations.wolfram.com/TilingTheHyp...

26.07.2025 00:33 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0
A tiling of the hyperbolic plane in the disk model with 10 regular pentagons at every vertex; this time the image is centered on one of the pentagons.

A tiling of the hyperbolic plane in the disk model with 10 regular pentagons at every vertex; this time the image is centered on one of the pentagons.

26.07.2025 00:28 β€” πŸ‘ 3    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
A tiling of the hyperbolic plane in the disk model with 10 regular pentagons at every vertex.

A tiling of the hyperbolic plane in the disk model with 10 regular pentagons at every vertex.

26.07.2025 00:07 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
from β€œDoes one have to be a genius to do maths?” by Terry Tao:
"The answer is an emphatic NO. In order to make good and useful contributions to mathematics, one does need to work hard, learn one’s field well, learn other fields and tools, ask questions, talk to other mathematicians, and think about the β€œbig picture”.
...
The number of interesting mathematical research areas and problems to work on is vast – far more than can be covered in detail just by the β€œbest” mathematicians, and sometimes the set of tools or ideas that you have will find something that other good mathematicians have overlooked, especially given that even the greatest mathematicians still have weaknesses in some aspects of mathematical research."

from β€œDoes one have to be a genius to do maths?” by Terry Tao: "The answer is an emphatic NO. In order to make good and useful contributions to mathematics, one does need to work hard, learn one’s field well, learn other fields and tools, ask questions, talk to other mathematicians, and think about the β€œbig picture”. ... The number of interesting mathematical research areas and problems to work on is vast – far more than can be covered in detail just by the β€œbest” mathematicians, and sometimes the set of tools or ideas that you have will find something that other good mathematicians have overlooked, especially given that even the greatest mathematicians still have weaknesses in some aspects of mathematical research."

Independent of thinking about AI, Terry Tao himself has an interesting and encouraging perspective regarding that first question:

19.07.2025 00:48 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

Excited to say, "looking forward to it!" πŸ™Œ

14.07.2025 02:18 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

Misread that as "origami".

12.07.2025 05:06 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

It's okay, you can rate my response a 0%. πŸ˜† Thanks for putting up with it.

10.07.2025 05:34 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

Kind of joking, but just using a discrete metric: how far is this rectangle from being a square? Well, if it's not a square, it is 100% far from being a square; and if it *is* a square, then it is 0% far from being a square. It's like a graph theory metric: you are either at the spot, or not.

10.07.2025 05:15 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

Probably 100% most of the time, but every once in a while 0%.

10.07.2025 04:56 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

πŸ˜… Welcome! At least the weather ought to be relatively nice during your visit. Looking forward to your Sydney Ideas event on Thursday!

07.07.2025 07:37 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0
Preview
International Visitor Program - Sydney Mathematical Research Institute IVP August 2023 applications are due 8 August 2023, for July 2024–June 2025 visits (general applicants) & March 2024–June 2025 for Australian citizens/PR & NZ citizens.

Applications are now open for our International Visitor Program, open to #mathematicians to visit Aus 🐨 between July '26-'June 27, or March '26-June -27 (Aus/NZ citizens)
πŸ“… Apply by Aug 1, info:
mathematical-research-institute.sydney.edu.au/internationa...
Please share with your networks πŸ” #MathSky

03.07.2025 00:06 β€” πŸ‘ 6    πŸ” 7    πŸ’¬ 0    πŸ“Œ 1

Please mail me my earned Certificate 0 with Honors at your earliest convenience. πŸ‘¨β€πŸŽ“

01.07.2025 08:30 β€” πŸ‘ 3    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
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β€œ21st century mathematics”: a free month-long online enrichment program for math teachers.

Info + register: bit.ly/21math2025

Video part 1:

23.04.2025 13:10 β€” πŸ‘ 19    πŸ” 10    πŸ’¬ 1    πŸ“Œ 2

πŸ˜„

27.06.2025 14:12 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
Preview
What's Wrong with This Picture? Amazon.com: What's Wrong with This Picture?: 9781559535847: Michael Serra: Books

"What's Wrong with This Picture?" by Michael Serra pops to mind.

www.amazon.com/Whats-Wrong-...

27.06.2025 14:07 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0
Stevin made a number of other important advances in the study of the real numbers. He argued strongly in L'Arithmetique (1585) that all numbers such as square roots, irrational numbers, surds, negative numbers etc should all be treated as numbers and not distinguished as being different in nature. He wrote:-

"Thesis 1:   That unity is a number.

Thesis 2:   That any given numbers can be square, cubes, fourth powers etc.

Thesis 3:   That any given root is a number.

Thesis 4:   That there are no absurd, irrational, irregular, inexplicable or surd numbers.

It is a very common thing amongst authors of arithmetics to treat numbers like √8 and similar ones, which they call absurd, irrational, irregular, inexplicable or surds etc and which we deny to be the case for number which turns up."

His first thesis was to argue against the Greek idea that 1 is not a number but a unit and the numbers 2, 3, 4, ... were composed of units. The other three theses were encouraging people to treat different types of numbers, which were at that time treated separately, as a single entity - namely a number.

Stevin made a number of other important advances in the study of the real numbers. He argued strongly in L'Arithmetique (1585) that all numbers such as square roots, irrational numbers, surds, negative numbers etc should all be treated as numbers and not distinguished as being different in nature. He wrote:- "Thesis 1: That unity is a number. Thesis 2: That any given numbers can be square, cubes, fourth powers etc. Thesis 3: That any given root is a number. Thesis 4: That there are no absurd, irrational, irregular, inexplicable or surd numbers. It is a very common thing amongst authors of arithmetics to treat numbers like √8 and similar ones, which they call absurd, irrational, irregular, inexplicable or surds etc and which we deny to be the case for number which turns up." His first thesis was to argue against the Greek idea that 1 is not a number but a unit and the numbers 2, 3, 4, ... were composed of units. The other three theses were encouraging people to treat different types of numbers, which were at that time treated separately, as a single entity - namely a number.

Simon Stevin, what a hero.

mathshistory.st-andrews.ac.uk/HistTopics/R...

27.06.2025 05:23 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0
Two years after the publication of Hankel's monograph, MΓ©ray published "Remarques sur la nature des quantitΓ©s" in which he considered Cauchy sequences of rational numbers which, if they did not converge to a rational limit, had what he called a "fictitious limit". He then considered the real numbers to consist of the rational numbers and his fictitious limits.

Two years after the publication of Hankel's monograph, MΓ©ray published "Remarques sur la nature des quantitΓ©s" in which he considered Cauchy sequences of rational numbers which, if they did not converge to a rational limit, had what he called a "fictitious limit". He then considered the real numbers to consist of the rational numbers and his fictitious limits.

TIL that we narrowly missing lugging around not only the monikers "imaginary", "negative", "complex", and "irrational" for numbers, but also "fictitious limits". Real glad for that. πŸ˜…

from MacTutor's "The real numbers: Stevin to Hilbert"

27.06.2025 04:32 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

Thanks for sharing!

27.06.2025 03:01 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

+but some of the lead up smaller questions you ask on a given problem might be known and/or standardly tractable/checkable? That's my guess of your meaning. Glad to hear more!

26.06.2025 20:41 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

This is wonderful, Peter, both the collection and the news from your student. Can you say more about the phrase "mathematicians might not know the answers to"? I'm curious about the wording, the "might not" in particular. Is this because you know the main problem in each of your Problems is open,+

26.06.2025 20:34 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 1    πŸ“Œ 0

Received! Glad to have you aboard, looking forward to it.

26.06.2025 04:30 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0

We must hang around different crowds, because I've heard literally no one say that this will not be terrible! πŸ˜†

Thanks for sharing!

24.06.2025 06:02 β€” πŸ‘ 0    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0
The magic of Fibonacci numbers | Arthur Benjamin | TED
YouTube video by TED The magic of Fibonacci numbers | Arthur Benjamin | TED

As a math appetizer for the program, here is a six-minute TED talk by mathematician Arthur Benjamin. The talk features the Fibonacci numbers, one of the two math topics for this year's program. (The other is bubbles!)

www.youtube.com/watch?v=SjSH...

23.06.2025 14:03 β€” πŸ‘ 1    πŸ” 0    πŸ’¬ 0    πŸ“Œ 0
Preview
21st century mathematics – 2025 An online learning experience for math teachers Registration for the 2025 program is now open! Here is the registration form. Registration will continue through the start of the program in July. If…

All the info and the registration form can be found here:

justinlanier.org/21st-century...

Please pass this along. And if it's a good fit for you, I hope you'll join in!

23.06.2025 14:03 β€” πŸ‘ 2    πŸ” 0    πŸ’¬ 2    πŸ“Œ 0
Photographs of eight mathematicians: Dr. Frank Morgan, Eve Parrott, Dr. Maia Karpovich, Dr. Emanuel Milman, Dr. Joe Neeman, Dr. Parker Duncan, Rory O'Dwyer, Dr. Eviatar Procaccia, Harun Khan, and Dr. Bernadette Faye.

Photographs of eight mathematicians: Dr. Frank Morgan, Eve Parrott, Dr. Maia Karpovich, Dr. Emanuel Milman, Dr. Joe Neeman, Dr. Parker Duncan, Rory O'Dwyer, Dr. Eviatar Procaccia, Harun Khan, and Dr. Bernadette Faye.

There are lots of chances for teachers to work on problems collaboratively, encounter new math ideas, and grow as teachers and mathematicians in community. We also have a great lineup of guest mathematicians who will visit us and share about their work.

23.06.2025 14:02 β€” πŸ‘ 3    πŸ” 0    πŸ’¬ 1    πŸ“Œ 1
A picture of a double bubble. A picture of the first 18 Fibonacci numbers, with the ones that are perfect powers highlighted.

A picture of a double bubble. A picture of the first 18 Fibonacci numbers, with the ones that are perfect powers highlighted.

We are two weeks out from the start of "21st century mathematics", a program I run for K-12 math teachers. (Register now!) The program helps teachers connect the math they teach with some math that has been discovered in the 21st century. The program is flexible, free, & online.

23.06.2025 14:00 β€” πŸ‘ 10    πŸ” 10    πŸ’¬ 1    πŸ“Œ 3

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