Po-Shen Loh: Mathematics, Math Olympiad, Combinatorics & Contact Tracing | Lex Fridman Podcast

Po-Shen Loh is a mathematician at CMU and coach of the USA International Math Olympiad team. Please support this podcast by checking out our sponsors:
- The Jordan Harbinger Show: jordanharbinger.com/lex/
- Onnit: lexfridman.com/onnit
- BetterHelp: betterhelp.com/lex to get 10% off
- Eight Sleep: www.eightsleep.com/lex and use code LEX to get special savings
- LMNT: drinkLMNT.com/lex to get free sample pack
EPISODE LINKS:
Po's Twitter: / poshenloh
Po's Website: www.poshenloh.com/
Daily Challenges: daily.poshenloh.com/
NOVID: www.novid.org/
PODCAST INFO:
Podcast website: lexfridman.com/podcast
Apple Podcasts: apple.co/2lwqZIr
Spotify: spoti.fi/2nEwCF8
RSS: lexfridman.com/feed/podcast/
Full episodes playlist: • Lex Fridman Podcast
Clips playlist: • Lex Fridman Podcast Clips
OUTLINE:
0:00 - Introduction
1:43 - Planes and bridges
5:21 - Writing a computer game from scratch
7:46 - Programming competitions
11:21 - Math is hard
16:52 - Contact tracing that preserves privacy
54:09 - Math Olympiad
1:09:49 - Hard math problem
1:17:06 - Is math discovered or invented?
1:22:02 - Intelligence
1:28:52 - Math education
1:33:03 - How to learn math
1:41:58 - Combinatorics
1:45:05 - Voting trees
1:55:29 - Stochastic coalescence
2:05:15 - P=NP
2:09:32 - Tolkien and WWII
2:11:52 - Advice for young people
2:13:57 - Meaning of life
SOCIAL:
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- Support on Patreon: / lexfridman

[@lexfridman]

Here are the timestamps. Please check out our sponsors to support this podcast. 0:00 - Introduction & sponsor mentions: - The Jordan Harbinger Show: jordanharbinger.com/lex/ - Onnit: lexfridman.com/onnit - BetterHelp: betterhelp.com/lex to get 10% off - Eight Sleep: www.eightsleep.com/lex and use code LEX to get special savings - LMNT: drinkLMNT.com/lex to get free sample pack 1:43 - Planes and bridges 5:21 - Writing a computer game from scratch 7:46 - Programming competitions 11:21 - Math is hard 16:52 - Contact tracing that preserves privacy 54:09 - Math Olympiad 1:09:49 - Hard math problem 1:17:06 - Is math discovered or invented? 1:22:02 - Intelligence 1:28:52 - Math education 1:33:03 - How to learn math 1:41:58 - Combinatorics 1:45:05 - Voting trees 1:55:29 - Stochastic coalescence 2:05:15 - P=NP 2:09:32 - Tolkien and WWII 2:11:52 - Advice for young people 2:13:57 - Meaning of life

[@alexandrenr]

Thanks Lex

[@jianfalco2133]

Thank you, Lex. 😌👍❤️

[@dudeshiya]

It sounds like some bottleneck argument used by Pitassi and Haken to prove lower bounds for the pigeonhole principle. Lex, you could maybe interview Tim Berners-Lee and talk about his work on decentralised internet. That would be interesting too!

[@shelly_cali_girl3594]

I would absolutely love the short videos of tidbits into your life. ❤️ Your podcast. This was a fantastic one.

[@shelly_cali_girl3594]

This is how I use to think 🤔 when smoking weed in my twenties.... 😂😂😂 Man.... If you got high... I wld get super deep. Great convo

[@relax-n-reads1514]

If Po-Shen Loh was my math professor back in school, I'd truly have a different perspective on mathematics. His passion is everything.

[@nelsoncastro7281]

🙄 yea it was the profs fault

[@nomathic7672]

Take responsibility for your own inadequacy.

[@BACKUP-nj7wg]

Straight get out of here with that nonsense 😂

[@dustin3213]

A child's mind can be guided and this is 100% true in many peoples lives

[@user-in1yw9ty5t]

I understand what you are saying. Now you know what it takes to have one. We all need to be one. Teach our inner child and improve on ourselves. If you never had a teacher like him be one and teach yourself.

[@ericlu8089]

"Teach not for memorization, teach to invent." In our day and age, you have all the knowledge already well known on the internet. What is valuable now is to how to use it to solve unknown problems for here on out. This quote has so much volume.

[@aeromtb2468]

The best thing my engr prof told the class is not to memorize the formula, figure out how to revive it , think and show it work. Helped me out during a license test, then I found the formulas at end of test but didn't need them.

[@infiniteinfiniteinfi]

@@aeromtb2468 Yeah, lets remember that quote ;)

[@grimendancehall]

You don't have all the knowledge. You can't just start reading complex technical material

[@elthgar]

Po-Shen Loh is just overflowing with joy. Very fun to listen to.

[@MrAntonioCapone]

Maybe that is the secret for eternal youth ? He is 39 according to Wikipedia.

[@gror7849]

"You have the power to invent also" - this is what a teacher should do. Unleash the students potential...not set them on a predetermined path and create just a "human copy" of the manual the teacher is using. I enjoyed this soooo much!!!

[@jamesr2936]

This podcast always brings it, Lex - A wealth of interesting guests and the scope of subjects covered is eye-opening.

[@alexjbriiones]

I wish we could have more people like Po-Shen Loh. He is simply a great teacher.

[@Backflipmarine]

The thirst for smart conversation is quite real, I can never stand going to a lecture, but these podcasts I check daily for. Presentation and show of heart is everything.

[@elidwor1856]

It's so difficult to find high quality podcasts on technical topics. Thanks again Lex, these talks are amazing!

[@MrSmurfhawk]

Outline as percentages: 1 % - Introduction 3 % - Planes and bridges 2 % - Writing a computer game from scratch 3 % - Programming competitions 4 % - Math is hard 27 % - Contact tracing that preserves privacy 11 % - Math Olympiad 5 % - Hard math problem 4 % - Is math discovered or invented? 5 % - Intelligence 3 % - Math education 6 % - How to learn math 2 % - Combinatorics 7 % - Voting trees 7 % - Stochastic coalescence 3 % - P=NP 2 % - Tolkien and WWII 1 % - Advice for young people 4 % - Meaning of life (Rounding may create totals greater than 100%)

[@koroshiya_1]

This is lovely!

[@montanawildhack2760]

That was such a great convo, thank you so much for the access Lex & Po!!

[@krezkort]

Wow, I had to pause at times to let my brain calm down from all the ideas. Really like the description of learning as collecting insights; creativity being ability to stack them.

[@ronaldrodrigo6485]

love this conversation covering the spectrum of academic to practical impact to daily life

[@user-nf8bf6dr6f]

Lex, you should interview MIT people that made Julia language, looking deeper it's truly magnificent piece of modern engineering

[@Sliznark]

@@davidmack644 I won't claim to know all the differences but one I do know is how the sub root program reads commands from the host.

[@dominic8147]

@@davidmack644 computationalthinking.mit.edu/Spring21/ The guy who invented Julia teaches it at MIT and made the class discord open to the public. Obviously there's no grade if you aren't an MIT student, but you can ask questions during class and do the homework. The class is almost over. Maybe a week or two left, but you can still attend the last lecture or two :)

[@HeyRutvik]

Thanks for sharing the link,@@dominic8147.

[@kukuster]

@@kevyt3095 Don't mind *Panda Tobi*

[@guillem.590]

@@orangestapler8729 from what i've gathered, Julia is a high level high performance language. So you get syntax thats very readable (like python), but you don't have to compromise the performance (unlike python, which is rather slow). That being said, its more focused on scientific computing rather than, say, software engineering. The reason its a big deal is that most scientific computing applications (like optimization or numerical PDE) really benefit from being implemented with high level syntax, so the fact that now you can get that without having to put up with worst performance its great. If you want to know more i would recommend the article "Julia: a fresh approach to numerical computing" by Bezanson et al (2017)

[@tgwashdc]

Fantastic conversation. Packed with so many ideas, I have to pause, relish and then move on. Keep up the good work Lex and Po-Shen!

[@drover7476]

Loved this episode, absolutely love the way Po communicates maths and computing.

[@mistorya600]

I love that these type of people exist! Such a fascinating discussion to listen to.

[@sriragvuppala4332]

I'm incredibly grateful for this episode! Thank you Lex!

[@jackdouglas7057]

Fantastic episode! Very insightful conversation around math competitions

[@joshuastudebaker678]

Love Po-Shen's vibe. So chill :) Very enjoyable Podcast!

[@anavilhelminaverdnik685]

Amazing episode! Engaging the scientific community is what makes this podcast stand out. Looking forward to more interviews like this!

[@asadalbra]

Very, very, very happy knowing people like Po-Shen Loh exist

[@Av-fn5wx]

18:30 such a sweet moment. Professor being his humble self & Lex not failing to appreciate his efforts in a witty manner. Thats how 2 intelligent people communicate

[@samienaamien7038]

I'm 60, and I want Po-Shen Lo to teach me!!! he's making me fall in love with Math! And you know what, as I was typing this, Lex asked about learning Math as an adult! Serendipity!

[@gena8414]

change your diaper grandpa

[@samienaamien7038]

@@gena8414 What a pathetic attempt at humour. Shame...

[@huwphillips2696]

Very glad you've interviewed Po, mega interesting guy, well done Lex.

[@blindlfaithful]

Thank you once again Mr. Fridman.

[@kristofferh2312]

Holy hell Lex, your episodes have been top notch lately !

[@cyclotrojan]

lately ?? more like since forever

[@erictko85]

This man is extremely refreshing and an inspiring person to listen to. Thanks for another great conversation Lex

[@erictko85]

@Lex. Frìdman What have you done with Lex?

[@ikarusxv]

I like how Lex always see the philosophical part of everything

[@Tubingonline1]

Phenomenal interview, cannot imagine life without lex's podcast. Lex's score might already be higher than most human beings: 2:14:53 You do not need to invent a better coffee machine, i guess, you already have invented something amazing - Lex Fridman podcast.😊

[@robertmontgomery2047]

One of my favorites Lex, thank you!

[@thequantartist]

I learned so much from that podcast, thank you!

[@bingbong2179]

I just finished reading Neal Stephenson's book Anathem, and at the 1:20:00 mark where Lex starts talking about communicating with other races through math's theorems, it's crazy cause that's kind of a key feature within the novel and both ideas I've encountered for the first time in the last two weeks. It's crazy. The more that you do productively in terms of exploring ideas and fun conversations, the more coincidences you notice. And the rush of joy at noticing analogies to some past experience in a different field is one of the best and simplest pleasures around

[@skadoosh5045]

Beautifully said :)

[@AgentAaron]

So happy to nerd out on this podcast! Thanks Lex, thanks Po! And away we go...... :)

[@woudschoutteten1397]

I love the way he goes “ahh”

[@anoopramakrishna]

Really looking forward to the tutorial videos you alluded to

[@vasylmyeshkov7791]

Highly inspirational video. Thanks, Alexey!

[@watari3]

One of the best interviews.

[@CipherOne]

I love this guy. This is brilliant. Thank you both.

[@Legola87]

Wow, awesome Qs and even more awesome answers!

[@marufmamun6592]

I think that daily mental exercise you mention is a great practice. If I take at least 30-60 minutes to think clearly about some questions daily, I find myself being more deliberate throughout the day, and being more myself. Otherwise I go through my day almost like a robot, not really thinking about why I'm doing what I'm doing.

[@NomadicBrian]

Is this clarity? Where has it gone? In a box replaced by ambiguity.

[@rr2961]

Nice to see you interviewing worthwile guests again :)

[@mjharris7417]

Prof. Loh, Thank you for your visit to NC in 2023, your respect for PEOPLE spoke so loud I don’t remember what you said😮. The process to show then ask participants to repeat 20 times. Reminds me of how I learned Pivot Tables over 20 years ago. Still working to solve the INCENTIVE challenges.

[@adriennebelle3338]

I love the decoration to match the conversation :)

[@aeromtb2468]

These two guys talking about an application as a real tool to prevent future cases, not just for 2020 virus, is hopefully. The two smartest people in the room and maybe the city!!!

[@zaks7306]

Thanks for a fascinating conversation

[@cyclotrojan]

thanks for the timestamps, proud to support this man on patreon

[@shaneckel]

Yooo! Po-Shen is the shit. I had the opportunity to run into him several times at CMU and it was always a pleasure. It still bums me out I couldn't help him in some way with his company. It was a blast talking to him. Great podcast Lex.

[@canopusinthenorth]

Lex, this is a fantastic interview. Curious on how you will come up with your daily math habit. I have been doing it for a while now and doing Math first thing in the morning works for me. Wake up, Make Coffee, Do math.

[@Danielfaust0]

Amazing conversation. Thanks

[@randomperson3457223]

I worked on NOVID with Po. He's AMAZING!!

[@haythamal-dokanji9547]

Great conversation and a very likable guest. I think trying to solve computer programming problems using algorithms is similar to solving mathematical problems and perhaps provide the same advantages. This can also be a nice daily or bi-weekly routine.

[@mikely7354]

Dang it. Conversations on this channel is always intelligent and interesting. Why can't all podcasts be like this?

[@SK-kj1ge]

Can you imagine if your math prof was this super cool, friendly, passionate, hilarious?

[@Manicscitzo]

No doubt, Po-Shen is a great math teacher, more than other subjects I think you have to really understand it deeply to make it beautiful, fun and intuitive. Unfortunately there's nowhere near enough people like that to staff universities let alone high schools so people often have a negative view of learning math.

[@jareddiliberto60]

Looking forward to the Lex Cinematic Universe. Keep the content coming

[@luxsasha]

love this podcast!!

[@DNJ9o9o]

I remember him from the Pi day video! Love his passion

[@Justsayingmythoughts]

Discovery versus invention. It seems like everything is just discovered when I start to think about it.. . Certainly shares a fine line.

[@lucasa8710]

the initiation of this episode had me smiling the hole time

[@ACactusHealingRhino]

dude this podcast keeps getting better and better i cant believe it

[@billynollii7396]

CMU is a great place. My daughter was a crash hot HS student, and was put on a wait list there. Later, got a chemical engineering degree elsewhere, but I digress. Great interview. I enjoyed it.

[@LDdrums20]

What a fantastic guy! Fascinating!

[@rishabkumar9578]

He is a very good man. Should learn lot of things from him.

[@danh5226]

really like the second half of this episode

[@pfever]

I just saw this idea of contact tracing being applied in Taiwan now! Pretty cool!

[@shailajadsharma3516]

Thank you for the informative videos

[@xnxbxs_zx]

Thank you 🙌

[@TheRodster21]

I honestly don't like math but this guy makes me want to love it the way he does

[@craigbeare9770]

Here is a positive comment lex ! Read them you deserve it thanks for bringing intellectual disccusions to the masses

[@StanleyTam117]

I admire the way he trains his six math Olympiads with the goal of making significant contributions in the future, rather than just winning in _this_ game. This is truly golden!

[@StanleyTam117]

Just finished watching this video and I loved the talk. The energy that Professor Loh exuded was enormous and contagious!

[@genericname2284]

This dude has got to be top 10 most likable dudes on the planet. Incredible energy

[@halfdan7722]

This Guy is Amazing !!!!

[@defface777]

Po-Shen Loh is a very likable person

[@tenawalker5037]

That's Great! Thank you so much.

[@a3axon]

dude this guy showed me the best way to solve quadratics- no cap

[@superheaton]

1:05:16 NO OVERLAP :D What a nice professor that cares about the future

[@mockingbird3809]

Oh, I remember this guy from the video "The most beautiful equation in Math".

[@GffHll]

I will watch this, thanks !

[@Ayra_Is_Cool_lol]

Ohhh, thought he looked familiar

[@smartwolf9045]

As a computer scientist, this Channel is a mine of gold

[@user-co5cx6ez6r]

pls release those vidsssss 🥺🥺🔥🔥🔥🔥🔥🔥🔥

[@dyer308]

I love this guy!

[@user-co5cx6ez6r]

3rd time watching, just pure brilliance

[@ShivaRainchild]

His meaning of life is so fucked up & weird, I really like this dude. He seems to have found a way to conserve all the curiosity and energy most of us tend to lose once we reach adulthood. This was one of my favorite conversations this year. Thank you both very much! :)

[@daepak9099]

It's not fucked up or weird at all. He just sort of quantified a typical response of wanting to have an impactful contribution to future generations. It's actually quite clear, pragmatic, and sensible. What about his response do you find fucked up?

[@michailvolski5035]

not a good choice of words there

[@MiroslavaSotakova]

Lex - on daily math rituals: Solving IMO problems is my occasional meditation. Also, if you can't fall asleep in the evening, I recommend thinking about a tough problem (generally the 3rd and the 6th).

[@nhatminh4529]

What? You can solve IMO frequently? Are u a genius or sth?

[@MiroslavaSotakova]

@@nhatminh4529 There are 6 problems a year, so I usually check them out after the contest in summer (there is a ton of problems for training but I don't have time for that). The techniques needed to solve them are elementary, solutions usually take one creative idea. The geniuses are those who not only can solve them (most math majors should be able to do maybe a half at least) but can do so in 1.5h per problem for both finding a solution and writing it up. I usually can't :).

[@nhatminh4529]

@@MiroslavaSotakova Are you serious? It’s IMO, one of the hardest math competitions in the world. It takes years and years of hard work and intense math training for a person to be able to solve a single problem, or maybe still can’t solve anything at all. And I doubt that every math major can solve half of them, even PhDs. But since you can solve a lot of them, can u maybe give me some advice on how to tackle those problems? How long should I try to solve before looking at solutions? You are definitely way smarter than normal to be able to solve those incredibly hard problems.

[@user-co5cx6ez6r]

SUPER INTERESTED ! 🙋‍♂️

[@LarryZAR]

I've been waiting for this.

[@Bultish]

GREATEST SHOW ON EARTH

[@Pammy11J]

I love this guy, epic

[@nomoregoodlife1255]

happily surprised with this interview :D

[@nDreaw12]

Terence Tao would be amazing!! Great Video :)

[@caseyluostari5691]

Please do more on philosophy!

[@advaithbala3087]

“The most beautiful episode on math”

[@harrisoncentner6876]

Dr. Loh is SO cool!!!

[@ryantuohy6890]

This into was absolutely killer

[@ultrabellowman]

that part where he explain his teaching philosophy at 1:04:40 is how teaching should be, helping the student solve problems in that area

[@jdragon8184]

mathmeticians and competitive coders are purest creatures on earth

[@Smith1hfhdhdjd]

Super interesting guy! Great guest

[@necrobushido]

Good interview. I'm surprised that Arrow's Impossibility Theorem didn't come up during the portion on voting.

[@charliekirkham4336]

Lex, can you get more people from biotech? I know it's not your area, but no one is covering it like this. It's blowing up and we need people to explain the cutting-edge stuff that is happening.

[@Len124]

4:05 One of the best kind of structures for that experience, in my opinion, are those that rely on "tensegrity." They seem like they shouldn't work on an intuitive level because you're essentially holding up a table, monument, or even a building using, at least in a sense, rope, steel cables, or some other non-rigid materials as pillars, relying on tensile strength and particular weight distributions to create self-contained stability. Rather than treating gravity as the enemy of building upward, tensegrity ironically uses it to keep it the thing from falling down . It seems like the architectural version of pulling oneself up by the bootstraps.