Sunday, July 3, 2022

Korean Air (according to google translate)

A survey request from our recent flight:

대한항공과 함께 즐겁고 편안한 여행 하셨는지요?

고객님의 소중한 의견을 듣고자 설문조사를 실시하고 있습니다. 잠시만 시간을 내주시면 감사하겠습니다.

We hope you had a pleasant trip with Korean Air.

Please answer this short survey to share your valuable feedback with us.



The Korean text (according to google translate, my emphasis added):

Did you have a pleasant and comfortable trip with Korean Air?

We are conducting a survey to hear your valuable opinions. Thank you for taking a moment.

The Chinese text (atgt,mea):

You are invited to participate in a short survey to share your valuable opinions with us.

The Japanese text (atgt,mea):

We are conducting a questionnaire survey to improve service quality. Thank you for your cooperation.

Perfect numbers: Lichtman's Theorem (Part 1)

This summer, we are working through Jared Lichtman's recent proof that the primes achieve the maximal Erdős sum over primitive subsets of the natural numbers.

Quanta Magazine had a very nice article describing the theorem (formerly a conjecture of Erdős) which is the inspiration for this project. The article is here.

I will be posting notes on our conversations. The most important thing to understand: this project is about the journey and not the destination. We may not (probably won't!) get all the way through the paper. Along the way, we will take plenty of detours and excursions.

Wednesday, August 11, 2021

Possibilites for G4G

  1. misère version of go problems
  2. slinky tangles (more seriously, links with secondary structure for alpha-helix protein folding) 
  3. caesar cipher rotations: inspired by this which was probably mentioned on ACX or DSL
  4. Chebyshev machines with mindstorms
  5. multi focus version of ellipse (constant string length)

Monday, December 28, 2020

Queen's Gambit comments

Putting this here for no particular reason.

Queen's Gambit: B+/B. Entertaining, with some issues.



The ending was too perfect, but we knew something like that would happen from nearly the first scene (as soon as we knew Borgov's name). I wonder if it would have been better with a slight twist: if the final game had been a legitimate draw. Probably the general audience doesn't know this, but it is (now) very common for top level chess matches to end with a draw.  I'm not sure how common that was in the 60s.

To support that result, they probably would have had to lay a bunch of groundwork earlier.  maybe a game with Shaibel that ends with a drawn position and he has to explain why it isn't worth continuing to play? As it is presented in the show, a draw is just a trick, when one player thinks they have lost, but they think the other player doesn't see how to win, then they offer a draw as a psychological play on the lack of confidence.


They did, eventually, address all my major issues (drugs, genius). Also, the way they set up the team support was well done.  First, they show us that the soviet players are collaborating.  The audience  probably thinks that's cheating, but it serves to legitimize the support from the US players (which, as depicted, is pretty implausible, since it involves exactly the 6 serious male players who have appeared more than once).  Then, during play, Borgov deviates from the ideas the team had considered, so we see that Beth actually does win "on her own."


By coincidence, I just read The Big Bounce, a novel from the 60s.  One theme of that book was "women are bored and unsatisfied with life, have to turn to substances or craziness to occupy themselves." It is very condescending.  Unfortunately, there were also echoes of that in TQG: Beth herself, the society girl from high school, Beth's bio and adoptive mothers, Cleo.  Jolene and Packer(? the woman from the first chess tournament) are exceptions, but they don't get much screen time in those roles.

Perhaps would have been nice to see more of her bio mother. I didn't really understand what was going on with her, so maybe she was trapped. Didn't seem that there was anyone trapping Alma, the adoptive mother. There were nods to the idea of some generalized social pressure (the first Life interview, the society club high school student, the two women getting paired in the first tournament), but it was all pretty diffuse.  For example, we didn't ever see any US Chess Federation opposition to Beth playing in the open division for the US championship.


Other misc thoughts: 

(1) Beth's affection for Townes doesn't really ring true.  Fine that she had a crush on him for a while, but I didn't buy that it was a deep love simmering for years and years. 

(2) I didn't understand the lack of consistency in the post-sex scenes between Beltik and Benny. In the first, Beth is shown to be cold because she is immediately thinking about chess, but, in the second, she is shown not comprehending that Benny would immediately think of chess afterwards.  

(3) Cleo says (and Beth seems to agree) that Benny is only in love with himself. While we definitely see that he thinks highly of himself, he has clearly gone out of his way to help Beth, for no discernible benefit to himself.

(4) The Cleo sabotage evening had several things that didn't sit well.  First, Cleo knows that Beth has a big day ahead and completely undermines her. It was such an extreme degree that I almost thought there would be a reveal of Cleo getting paid off by the Russians or some other group opposed to Beth. Second, it shows Beth waking up in the bath. Could that possibly be a thing? If she were so unaware that she wouldn't notice the discomfort, wouldn't she drown?

Saturday, May 16, 2020

Chinese and Weiqi (go) videos

A collection of videos for studying go and chinese together, for J1:

— Beginning level tutorial, this series is made almost 20 years ago, classic but outdated (

— Beginning to mid-level life-death problems (

— Bad moves analysis (in Chinese literally translate to ‘smelly’ or ‘stinky’ moves) (

 — Ancient complicated life-death problems from the 1700s, some are doable, some are so massive and even challenging for pros (

  Ke Jie’s 15 best games voted by fans

— Pro game, commented by Ke Jie (

— AlphaGo VS AlphaGo 50 games (

— CCTV (China Central Televison) ‘s documentary about weiqi (

Tuesday, February 11, 2020

What is 8?

I've had a chance to spend more time doing math with the kids again and am hoping to write up our activities more consistently.  Let's see how this works out!

Graham Fletcher created a set of  Progressions videos for various elementary school themes. J3 and I recently went back to his page and found he had a new(er than we knew) progression on early number and counting.  Even for this simple topic, the video highlights some points we hadn't considered explicitly, for example distinguishing producers (of a number) and counters. Also, the cardinality point that smaller natural numbers are nested within larger numbers wasn't something we had talked about, but we soon realized it was part of many examples in how we understand numbers.

With that as inspiration, J3 and I decided to search for a range of examples of a single number, we chose 8, in different forms.  There is at least one obvious version we're missing.

Add a comment (with picture, if you can) to show other forms of the number 8!

Marking 8 on the 100 board, an easy place to start:

8 beads on the abacus shows the relationships 3+5 = 8 and 10-2 = 8 (also 100- 92 = 8)

8 can hide in plain sight. Without labeling the three lengths, it would have been hard to recognize the longer one as 8 cm and, for you at home, impossible to know without reference to show the scale.

It happened that, within the precision of our scale, two chocolate wrapped chocolate bars were 8 oz (2x3.5 oz of chocolate + about half an ounce of wrapping for each):

8 cups of water ended up being a lot, so this version unintentionally revealed a relationship 4 + 2 + 2 = 8

Though I'm not sure I can articulate why or show supporting research, I feel it is very valuable to build experience with physical models of numbers to create familiarity and intuition about what they are/mean. In particular, I hope this helped J3 anchor the importance of units of measure and scale in the interpretation of numbers.

Finally, this construction has nothing to do with the number 8 (or does it???)

Thursday, May 30, 2019

Quick 2019 resources for parents

A quick list of resources for an elementary school parent

Resources depending on prep time:
  • Grab-and-go

  • More prep time, in increasing order of advanced time required
    • the puzzles and games are very good. 
    • Math Teachers at Play blog carnivals:  Variable amounts of prep time, but usually there’s at least one activity that is ripe for exploration, may take a bit of reading through the carnival to find a suitable one.
    • Mike's Lawler's blog: wonderful collection of (mostly) videos of his family working through problems, puzzles and mathematical explorations. Because his kids are older, it will take a little time to find something you think is suited for your son and then a bit to organize the activity.
    • Georgia State math standards: Despite the name "standards," these documents have a full curriculum with a collection of really great activities. As with any full curriculum, not everything is a complete winner, but there are enough gems. Also, this is probably the best resource for finding material to complement a kid's weaknesses.
This page is still the most comprehensive list of our favorite resources:
Unfortunately, it is a little dated as I haven’t really been maintaining this blog in the last 2 years.