Midterms

I accidentally took a midterm today. (This is the second time that this has happened!)

Hello from Chicago!

I don't want to think about it too much, but yikes, I have become a graduate student! I arrived in Chicago last Saturday (9/13) but the dorm I'm living in isn't available until next Sunday, so I'm staying with Minh-Tam for now.

Minh-Tam's wifi has not been set up yet (because Comcast never showed up to set it up...), so I'm currently writing this in the hallway of his apartment, sitting where I have wifi signal from another friend who lives in the same building. I probably look really strange doing this. I don't think I should sit here too long, so for now, here's a picture of Chicago that I took when I arrived.

"Miller's Pub" in the Chicago Midway airport.

There's actually a story behind this picture: when I visited Chicago back in March, I flew in with 5 other friends. Several of us knew Professor Miller from the SMALL REU so one person suggested taking a picture of this restaurant to send to the professor. I was tired from the flight so I said I would remember to get a picture when we were leaving Chicago.

Three days later, our visit to Chicago was over. As I was heading to the airport in the morning, I accidentally left my camera in the taxi, so I didn't get to take this picture back in March. That's why I took this picture now -- better late than never! (The way I got my camera back is a pretty amusing story too, maybe for another time.)

PAX Prime 2014!

(I should have made this post several weeks ago. So despite it being 9/18, I'm going to set the date to 9/2.)

I was lucky enough to be in Seattle when PAX Prime was taking place. I'm not much of a video gamer but it was still fun to see all the upcoming games.

I played a lot of Tetris Attack (and later versions) that weekend. Like in the picture below!

The level is set to 10 (you might be able to see if you look close enough), so after I took this picture, I immediately lost!

The picture is from a room where you can borrow games and play them on the various consoles they have! As we were returning our game, we saw two other people playing Tetris Attack at another station. We naturally paused to watch them play. The player on the left had some garbage blocks.

Player on left: *raises his tower of blocks*
Andrew: "Ohh look! He's setting for something!"
Me: *agrees with Andrew and expects that player to clear the garbage blocks and start some long chain*
Player on the left: *immediately loses*

I bursted out laughing. Luckily the sounds from all the video games from all the stations made it so the player couldn't hear me (I hope?).

Congratulations to Professor Bhargava!

It was announced this week that Manjul Bhargava won the Fields medal! I'm not that surprised to hear this; after all, in the months prior to this one, I heard so much speculation that he would win the award. And I heard many times about his amazing mathematical achievements. When the Princeton math department celebrated Yakov Sinai winning the Abel prize this May, I mentioned to people how sad I was that I would not be around when Professor Bhargava wins the Fields medal.

What did surprise me was that many of my friends started contacting me, telling me they saw me in the video on Bhargava that was released together with the announcement of the Fields medalists. (In fact, it was played on big screens to thousands of mathematicians at the International Congress of Mathematicians.)

I'm watching the video from my desk at Facebook!

How did I end up in that video? I knew Bhargava was away from Princeton the whole school 2013-2014 year, so I was quite surprised to see him appear in the common room one day in May. I went up to talk to him and he explained he was back because the Simons Foundation wanted to make a video about him that was set at Princeton.

Then he asked me if I wanted to be in the video. I decided to go along with it. (It sounded like fun!) There were several other students that were also pulled into this video production.

The videographer following him around (who I didn't notice at first) asked me and the other students to do several things with Bhargava, including:

1. walking into the common room and taking seats at a table
2. listening to Bhargava teach us a card trick
3. walking out of the common room

Only the card trick parts made it to the video though.

Weeks 3-5

Week 2 (6/16)

On Saturday, Facebook took the interns white-water rafting! (I don't have pictures of actually being on the river. You can probably guess why.)

On Sunday, I walked down to Chinatown (and bought some Asian groceries).

Week 3 (6/23)

Mini-golfing in the middle of the week.

Facebook has "Free Lunch Wednesdays." A group of us went to lunch in Capitol Hill at a restaurant called Sitka and Spruce.

Princeton students in the area went hiking on Tiger Mountain (very appropriate for Princeton). We went on a trail called Poo Poo Point. (I don't know if that name is appropriate for anything!)

Everyone seems happy to be at the top!

I joined Facebook in the pride parade.

It was a large group of Facebook people. And the interns were at the front.

Week 4 (6/30)

I checked out the 4th of July festival at South Lake Union park.

Another Free Lunch Wednesday!

Week 5 (7/7)

Facebook had a Hack-a-thon this week (Wednesday to Friday).

S'mores-making on the first night

And they ended the Hack-a-thon by inviting a soccer player to the office.

Picture with DeAndre Yedlin

Weeks 1-2 of Facebook internship (out of 12)

Got back to California just in time for PHHS's math team party!

Followed by Facebook's intern orientation in their Menlo Park HQ!

We sat in this room and listened to many people talk.

There's too much food in the offices. Hopefully I won't become fat this summer!

After the week-long orientation ended, there was a Rubik's cube competition in Sunnyvale!

Then it was off to Facebook in Seattle!

Breakfast in the cafe on the first day!

The cafe has a nice view.

Two graduations in one week

I graduated from Princeton on Tuesday. Making it through the commencement ceremony was probably the hardest thing I had to do to get my diploma. We sat in the hot hot sun for hours while important people talked (either in English or in Latin). I solved my 8x8 once but then the puzzle got too hot (!) so I put it away.

It was super sunny! Luckily I had my hat.

After surviving that morning, Princeton kicked us out so I went to visit some friends in Boston. On Thursday, I attended the number theory conference at BU in honor of Glenn Stevens's 60th birthday. (Prof. Stevens founded PROMYS.)

Conference banquet!

Also on Thursday, I sent an email to some friends in Boston asking if they were free on Friday. One of the conversations went like this.

Me: I'm in Boston! Are you free on Friday?
Rachel: ... Friday is our graduation!
Me: !!

Congratulations!

Also, Jennifer and I made scallion pancakes! We need to figure out how to make them layered though...

Scallion pancake!

Dead week so far

The last two days have been very nice and warm days. (They've also been sunny, but anyways...)

Yesterday I tried to read Thoreau's Walden outside. But after 10 pages, I fell asleep.

Today I tried to go for a 30 minute run through the Institute Woods (at the IAS). I got lost in the woods and the run ended up being 60 minutes. I entered behind the Institute and somehow emerged near the Lawrence apartments...

Google CodeJam, 5am, again!

Just see my post from a year ago. The exact same thing happened.

Highlights of this week

On Wednesday night, I ran into the grad student teaching History of Mathematics.

grad student: How did you find Descartes?
me: Descartes? ... Oh, is that what our reading for tomorrow is about?

Friday morning, I was interviewing for Microsoft.

me: "I run Linux on a Mac."
[few seconds later]
me (in my head): *oops*

Tuesday morning convocation

Me: (decides to take picture of Professor Loepp explaining NSF fellowships) *points camera*

Professor Loepp: Alan's taking a picture of the presentation. Alan do you want me to take a picture of you and the presentation?

Me: Actually, I can do it myself! *takes picture*

Dining Services doesn't understand logic

"if you are assigned a lunch shift on Friday, you will be provided with lunch, but you will not be provided with breakfast or dinner." (source)

(I have many other complaints about dining services as well.)

Google CodeJam

5am in the morning! Just in time for Google CodeJam Round 1C!

Update (7:30am): round just ended, made it to the next round!

Mathematicians at the Beethoven concert

Tonight, I ran into Professor Stein at the Beethoven concert, and he introduced me to Professor Shimura!

While jogging at 7am, I saw Professor Gunning in front of his house getting the newspaper!

Smashing two planes together?

Minh-Tam and I were just discussing algebraic topology, and now we're wondering the following: what do you get when you smash two planes together?

(By that, I mean $\mathbb{R}^2 \wedge \mathbb{R}^2$, where $\wedge$ denotes the smash product.)

Stay tuned! (I will figure out the answer.)

fork() explosion!

Quick summary: I discovered that an infinite loop calling only fork() is a terrible idea. I hope I don't get an angry email from a system administrator any time soon!

I've been home for two days, and my goal has been to finish the Unix Shell assignment for my programming systems class.

Just a few minutes ago, I learned how important it is to be careful when working with system calls like fork(). I wrote a program (on the Princeton server) which consisted of an infinite loop that called fork() once for each iteration. It seemed like a pretty harmless program. After, all I could always use Ctrl-C to terminate the infinite loop, right?

Wrong. And it should have been clear from the start that this was a terrible idea. Each child process created by the fork() is another infinite loop that spawns infinitely many more child processes! And this continues recursively! So my original process and all its children were soon taking over the entire system! Ctrl-C didn't work, so I closed the terminal window and logged back in.

Issuing the top command, I could see hundreds of copies of my program running, and taking up over 90% of the system CPU. After unsuccessful attempts to kill all these processes, a system administrator must have realized that something was wrong and terminated everything for me. Now, things are back to normal (or they seem to be at least).

Oops. I hope I don't get an angry email from a system administrator any time soon!

LaTeX test

$a^2 + b^2 = c^2$

Knowing math jokes helps for the Putnam!

I spent 6 hours on Saturday 12/1 on the Putnam 2012 Exam. In both parts, I solved the first two problems in an hour, and spend the remaining two hours making no progress. But my favorite part of the exam was how I solved B1.

Let $S$ be a class of functions from $[0,\infty)$ to $[0,\infty)$ that satisfies:

(i) The functions $f_1(x)=e^x-1$ and $f_2(x)=\ln(x+1)$ are in $S;$

(ii) If $f(x)$ and $g(x)$ are in $S,$ the functions $f(x)+g(x)$ and $f(g(x))$ are in $S;$

(iii) If $f(x)$ and $g(x)$ are in $S$ and $f(x)\ge g(x)$ for all $x\ge 0,$ then the function $f(x)-g(x)$ is in $S.$

Prove that if $f(x)$ and $g(x)$ are in $S,$ then the function $f(x)g(x)$ is also in $S.$

This probably at first looked super complicated, and I wasn't sure how to start. But then I thought of the following math joke:

Noah's Ark lands after The Flood and Noah releases all the animals, saying, "Go forth and multiply." Several months pass and Noah decides to check up on the animals. All are doing fine except a pair of snakes. "What's the problem?" asks Noah. "Cut down some trees and let us live there," say the snakes. Noah follows their advice. Several more weeks pass and Noah checks up on the snakes again. He sees lots of little snakes; everybody is happy. Noah says, "So tell me how the trees helped." "Certainly," reply the snakes. "We're adders, and we need logs to multiply."

(Source: http://www.math.utah.edu/~cherk/mathjokes.html)

And soon after I remembered this joke, I wrote down a solution!

Sieves!

Our most recent problem set in Analytic Number Theory focused on sieves, so I have been thinking nothing except them. And this is true even though I turned in the problem set already! Two incidents this week:

• While I was eating breakfast at 2D, someone asked for a sieve. My immediate first thought was "Selberg sieve or Brun sieve?" but I realized soon afterwards that she was referring to a kitchen utensil.
• I overheard a grad student asking Professor Sarnak in the common room about a problem, and at one point, Sarnak asked "are you familiar with sieves?" I screamed out "I know how to do it!" across the room, and they turned around and stared at me. Sarnak then told the student "that young man can't solve this problem, but he can give you good upper bounds." And they went back to their discussion.