DIMACS
DIMACS REU 2017

General Information

Student: Jakub Svoboda
Office: CoRE 444
School: Charles University
Facebook: Jakub Svoboda
Project:[It's complicated and hard and about hardness]

Project Description

We are working on a project with our advisor Periklis Papakonstantinou. As a group we also have our own projects to solve and a couple of pending papers to attend to. The czech group consists of Jarda Hančl, Matěj Konečný, Jana Novotná, Radim Předstíraný, Václav Rozhoň, Jakub Pekárek, Štěpán Šimsa and myself.

Weekly Log

If you want more conventional log, you should look at Jakub Pekárek's page.
Prolog:

I was really happy when I heard that I was accepted to REU DIMACS program.

Yeah, that was February. My life was pure and unspoiled with real science. Now, I am here sitting on my bed and thinking about future, and past. How I got here and what I will do.

I don't know if I can make it, so I am writing this log to future generation to avoid my mistakes.

Week 1:

This week we travelled from cozy little Czech Republic to this place. We were welcomed with waving (W). And pizza.

But during the night, I realized this. We need to publish, otherwise, we are doomed. Everyone was really friendly, but I recognized hidden threat behind their eyes. I woke up very early, partly because of jet lag, but also because of the fear of not publishing.

The next day we met Periklis. He was really friedly and presented three problems for us. When I was sitting in this conference room, I was feeling hope. Maybe, just maybe, we are not doomed after all. But then Periklis dissapeared and with him, hope.

Then the nightmare started, bureaucracy. It is not their fault, they wouldn't do if they didn't have to. Even papers seemed harmless, but I can read between the lines. And as I read, I started sweating, with ice cold sweat.

There was eight of us. But Radim, he was weak, he didn't think that he would publish paper. One day, he started talking nonsenses, something abour gender studies. We thought that the next day, he will be better, but last time we have seen him running to the woods and licking Poison Ivy.

Even though we lost Radim we had really productive day. We were thinking about some sparse matrices and we had some results. Then we realized that we made a huge mistake, we were discussing the problem in the corridor. There was probably someone who could hear us and plagiarize our work. This feeling was multiplied by the fact, that in the corner there was person with cape taking notes (my guess is Lobachevsky).

Today is Saturday, but this means no rest for us. We celebrated Saturday with early waking, cold shower and even breakfast (not very usual). Then we spend around six hours with Periklis. We learned that one of our problems will be about hardness and it will be really hard. But anyway, this was really productive and because it was Saturday, no one stole our work.

Week 2:

This week was very rough. We've got another problem (except the problems described in Jakub Pekárek's page). It is about interactive cooperative protocols and we call him AGAR (Associative Groups, Antonovskyi-Robertson) problem. We are making progress with this.

We were working in our pace and all went well, but on Wednesday, we got a letter. In the letter there was Radim's right hand and the letter started: "So, you think you can handle the situation...". After we had seen this, we discarded the letter. We don't want to read any bad puns involving hands if we are solving our AGAR problem.

The next day we thought about it. We don't want to read the letter, but Radim can be useful, he can give us helping hand. So we tried to figure out who had sent the letter. We knew only that the man was tall, with wooden leg, had hook instead of his left hand, patch over his eye and was saying: "Ho, ho, ho". Yeah, that was what we were afraid of. He was a hipster! So we postoponed the investigation to the next week.

On weekends, Rutgers U is very dangerous place. So we decided to play a little trick on all paper stealers. We left two expandables (yes, Matěj was one of them) in Silvers and we went to Appalachian trail with all proofs and unpublished papers. We hoped that no stealer will suspect that.

We went to New York (dangerous, too much people, too hot, our papers almost self-ignited) and then to Garrison. Our plan was to sleep in a shelter near the railroad. This seemed like a good idea before we had seen that the shelter is actually bower (Here is my English little a insufficient, if you know the right word, write me.) for weddings and for endings of romantic movies my mom watches. But it was dark and we didn't have other place to sleep, so we settled there. The bower was like five meters (3.3422 × 10-11 AU if you want your crazy units) from Hudson River, so during night it got colder. It was very very cold and also the trains were not helping to create perfect sleeping conditions. Every hour there was train for each of the directions (two). And every train reported itself with a loud TOOT. Yeah, that was a perfect place, no one would suspect us to be there.

After a good night's sleep (if you count lying awake freezing in your sleeping bag) we got to the trail. First day went well. We visited Anthony's Nose and then remains of the Fort Montgomery. This was a famous place of American defeat. They tried to impress us, but we weren't impressed at all. In the Czech Republic, almost every hill or valley is famous place of Czech defeat, so for us it was quite boring.

After Fort Montgomery we climbed Bear Mountains (no bear seen). And then we sometimes happy, sometimes exhausted, continued to Fingerboard shelter (next to Lake Tioraki). We don't know where, but we made a mistake. Thankfully, this was not crucial. Probably we were talking in Czech and somebody heard us and reported to Rugers Intelligence. Not knowing that, we went to sleep peacefully, only bit afraid of bears (no bear seen). Jardáč was the most frightened, but after I told him that by the bears, they only mean koala bears, he calmed a little bit.

It started at night. Lazaros Gallos came. It was him, we are sure, we think that he was only making sure that we have some results worth publishing. But we can not tell him. Ever. Stealers would torture him for our results. He was dressed in bear costume. First, he checked if Štěpán is sleeping well. He wasn't, since he was afraid that our papers could be stolen. Then he found our bags. He ripped some of them and ate our breakfast (we hope that there will be pizza soon), but he didn't find the results, so he left. (one Lazaros Gallos seen, but there is slight chance that this was a bear)

Our photo from the night

The rest of the trip was relativelly boring. Only Štěpán was hungry and tired, but we were in the hurry, so we left him on some random train station. He will starve to the death soon, so we are not worried that our results will get to the wrong hands.

Week 3

In the night (Sunday to Monday) Štěpán has came. He had some hairs white, he was much more skinnier and with every louder sound he hid under the table. We gave him chicken soup , helped him to change his clothes, because his was really torn and then we put him to the bed. (Ok, it wasn't as much chicken soup as only water that poured from frozen chicken.) (Ok, we didn't really gave him new clothes, just changed his trousers for t-shirt and vice versa, it was really fun and he didn't defend himself.) (Ok, wasn't the bed, better description is fridge.)

But when we were asleep, Štěpán got his revenge. He was shouting loudly: "No, I don't have the proofs, take Matěj intead of me." and "No, not the ananas, not the ananas!!". He was really elaborate, when we checked him he looked like sleeping. This wasn't nice of him, we wanted to sleep. Yes, we left him in the wildest New Jersey, but that isn't reason to wake us up.

In Monday, we had the meeting. There is significant chance, that we wont publish our results. First of all, they might be stolen and published first by someone else. Secondly, there could be traitor among us and publish the results sooner then anyone else from the group. Thirdly, we can just forget what we have prooved. Fourthly, there can be some mistake, which we are not aware. Fifthly, we can do as we did in previous weeks and discover nothing.

We are basically OK, but we sould plan for all possibilities and one possiblity is that we will find Radim, then Trump resigns and then Pence and then Radim will be first one handed president of U.S. (Don't tell Trump where he was borned). The second possibility is that something will go wrong and we will not publish. Both the possibilities seems about equally likely to us, so we established two groups, one is taking care of Radim's inauguration speech and his first 100 days in the office, the second group, where I am, is taking care of escape plan if we will not publish.

The first group is doing really bad job. They have crazy plan. They want to dig trench betweent U.S. and Canada, it will be lowest trench of all. They say that will have the best heels and feels, whatever that means. They sounds so crazy that americans could actually like it.

The second group, where I am is doing better job. We made some progress with the agar problem and then we realized that if will not publish, then we cannot go back home. At least not by the plane. So we decided that we will swim home. That's why we started the workout. If we will not publish, then can at least get home that way. The other option is to do math in freezer of death (CoRE building) for rest of our lives.

An undated encounter with wildlife

I went for a walk the other night. As I was enjoying the campus I noticed the doe eating something next to path. "Wow, that is cool" I thought. I have seen them during day, but I have never took the picture of them. So I took the picture, but the picture was blurry and I didn't like it. Maybe if the doe would come closer, there would be better picture. So I started with calm voice lure the doe: "Don't worry, come closer". She probably didn't understand, because she started going back.

Maybe, if I would sit... Now, she is afraid, but sitting man is surely not threat. So I sat. She was constantly going back. Maybe she is afraid, because I am looking at her all the time. So I looked at her only occasionally, most time I was looking away or to my phone. And still with calm voice whispering: "Don't worry, come closer".

As I was sitting there for a while I started thinking about broader perspective: "Sh*t, I am seducing a doe." It is so wierd, but I want only picture. I should stop. But she is not going back, now she is completely ignoring me. That's good. I still have a chance! Even if I would stop now, I looked stupid, it can't get any worse. If I prevail, maybe I will get nice picture.

Now she looked at me, hurry, look at your phone. Ok, she started gazing, maybe there is my chance...

I was there for a while, but I didn't get nice picture. At the end the doe behaved as true gold digger. She followed the guy, with more expensive car and since I had no car, she followed the first guy with a car.

Week 4

From beginning of the week we were getting delicate signals, that Radim escaped his prisoners. In the night Štěpán heard scratching the window and then he swore that he had seen Radim's shadow. Then near our office in the CoRE building there was poster. When we looked closer, we had seen that it is not only saying "Equal opportunity in education", but under some letters is written: "Help me guys, I am starving, Radim" and the poster is dirty on some places. There must be cipher on this poster. We spend the day deciphering it. This wasn't easy cipher. At the end we noticed that if we will take the letters from the poster denoted by sequence starting at 100th decimal place of pi and then we will leave out some letters and at suitable places we will add letters f,u,g,o,i,e,d, then we get the message: Pls, left food in office, hungry. 73. Because 73 is Radim's favourite prime number starting with 7 and ending with 3 having the property that for every two digits in this number have difference at least 3. Vašek knew it because this number is his least favourite with the given property and he was arguing with Radim about it a lot.

The note could be fake, but we decided to trust it. We had this really old watermelon and we were thinking about throwing it out, so we just left it in the office.

And it worked! The next day, there wasn't any rotten watermelon.

The rest of the week we were talking with Radim in very secure way. We were doing our insanity workout, but in our moves there were some simple rules that allowed us transfer about 1 megabyte of data for each workout. Radim was watching us from secret location and then in the night he was knocking morse code on our walls. We tried to convince him to add us as his facebook friends, but Radim have facebook mostly for picking up girls and he do not want to have some weirdos in his friends, he didn't accepted ours friend requests yet, but we will talk him into it.

From the conversation we learned that Radim have made some progress with solving the group isomorphism problem. He had a time for thinking while he was tortured.

We agreed with Radim that we will meet him on Saturday in New York City.

After previous weekends we decided that this week, the main group with all our proofs will be truly random.

We went to New York and wandered around. We visited central park (Hey, New Yorkers reading this, you have very fat squirrels, you should do something about it.), Then downtown. The views was beautiful, but the meeting time with Radim was approaching. The meeting point was Statue of Liberty. We kinda knew where Statue is, but nobody told us that it is on the island. We got to the downtown Manhattan and suddently, sea. That was a problem, but we weren't desperate, yet.

There was some building with sign "Ferry" on it, so we, as good czechs, asked about the price of the ticket. We were really excited, that ticked was free, so we boarded immadiatelly.

Yea, we were pretty excited... Maybe too much.

Maybe, we should have asked where is ferry sailing before boarding.

We learned our lesson about ten minutes later, when we were passing by Liberty island.

If you are from New York, you probably know that we were sailing for about thirty minutes to Staten island.

Actually, you probably don't know this, because who in the right mind would go to the Staten island?

We were there, so we decided to be irrational and take a stroll. There was nothing much interesting around.

With Radim we planned everything. The plan for this case (case 34: Missed meeting because of confusion from NY public transporation) was to go to Brookling throught Brooklin bridge in the night and than do our spy thing (insanity workout).

Meanwhile, we ate in the best restaurant of its kind on downtown Manhattan... It was cheap thought... maybe because the kind of restaurat was McDonald and it was only 3.5 star rating among 3.3 star rating Macs.

In Brooklyn, because of Štěpán's dirty tricks it was me who must do the workout. We told Radim that we will meet in Boston, because we had some tickets to Boston. Actually, we bought them only to confuse enemies, but maybe they thought so and we will outsmart them.

The tickets was bought for 3am, Sunday. We had some time in Brooklyn, so we decided to be lost for a while. The plan went really well. We made it till 3am only because we were running from Brooklyn bridge.

In 7am we were in morning Boston. It was nice, so we took a nap in a park.But we had to found F-street. This was really difficult. First of all, we thought that Radim just censored the name of the street. From the looks of the people we asked about uncensored version, we deduced that this street is probably not in Boston.

All desperate, we discovered freedom trail. It was really good. We learned many interesting things about Boston and generally about US history. Too bad for Janča, she refused to visit any "historical" site if it isn't at least 500 years old, yea, she is spoiled european.

In the night when we were wandering aimlessly around Broadway (in Boston), we found F-street. And there was Radim. He told us his proofs and then everybody went his own way. We cannot be with Radim for too long, the proof stealers will use it.

So, after we got the proofs, in 3am, Monday, we went to NYC by bus and then to New Brunswick. Štěpán and Janča even made it to the meeting with our advisor.

We were bit tired, but happy we at least got something which looks like a proof.

The biggest challenge on Monday was not to fall asleep during the lecture. I failed it miserably... but with delight!

Week 5

This week was very short. We visited Princeton, but nearly nothing happened there. Except Jardáč had to dive for his aerobie... Mik became officially Czech... We had wanderful burgers and so on.

There is only one thing in Princeton I want to talk about. Einstein's house. Do not go there. Never ever. Period.

In this week we also visited IBM. It was too far and only half of the lectures was interesting, others were not. Food there was very good though.

During the way to IBM Štěpán introduced me to fanfiction book Harry Potter and the methods of rationality
. You should read it! Or maybe shouldn't... It is good, too good. It is the reason I did nothing during whole week.

Harry Potter intermezzo

"It's really good, I loved it. Harry Potter is more inteligent and scientific in this book, he really wants to know how magic works." said Štěpán. "Ok, I will try it, there is nothing to do anyway." So Štěpán opened laptop and found the book. And I started reading. And the bus was going to his destination.

"... Sorry, it usually works, but not now..." Some lady was explaing something about IBM. She had cool presentation monitor, this technology is used by at most ten people on the world and forty of these ten people would rather use their laptop. "If I will open my laptop here, she will notice me after about ten minutes that I am not paying attention. Maybe it is worth it... But then she will think that I am a jerk. Ok, I will wait."

Other darkened presentation room, few minutes after. "Ok, there, I will read. There is dark, nobody will see me."
"Laptop shines... ***."

Then there were lectures.

"Ok, this is really boring, she had my attention for twenty minutes, now it is over, I am opening the laptop."
"Maybe I can be seen, what if I lean back?"
"Ok, that's better, this is genious."

"Ok, this one is pretty good, I am not reading during this one..."
"Maybe a little?"
"Shut up!"

Then days went like this.

"Ok, it was a lunch. I should rest for a while, it is not good to work stuffed."
"Why is six now? I wanted to stop."

"Ok, I showered and I should go to sleep."
"But..."
"But what?"
"One chapter never killed nobody."
"Maybe... but in the morning I will be tired."
"Come on, it is only one chapter, this won't take more then 20 minutes."
"Ok, let's do this."
...
...
"You cheated! It's 3am!"
"It wasn't what you wanted?"
"Yes, I mean No!"
"Haha, you are mine now"

Week 6

During this weekend we discovered that proofs from Radim contained mistakes. It was bad. We tried to do something about it, but we failed.

To rest from all the math, we decided, that we will visit Washington (D.C.). We had some good experiences with night rides from New York. So we bought our tickets to 3:30am on Sunday.

Because of some programming competition Jarda went earlier to NY. Then I wanted to go with Vašek, but I had to do my workout. I tried to do it as fast as possible, but Vašek left during workout and I had to go to the shower.

Running, in the middle of college ave I realized that the shower was pointless. I was wet as I got from the shower.

Starring at the empty New Brunsvick platform, I realized that even running was pointless. Train and Vašek were gone. So I had 40 minutes to contemplate about my mistakes and how to find Vašek.

I tried to message him, but he didn't replied. So I decided to do some sightseeing in New York. During the day my main hobby was to imagine post apocalyptic New York. How would look the clans in New York if the society collapsed.

I really thought it throught. My favourite clan would be Defenders of the High Line. My second favourite would be The Battery Park Battalion... They would fight glorious wars with opponents.

New York was nice but truly interesting things happens after midnight. I gave up sightseeing and settled myself near Madison Square Garden and read.

While I was reading first chapter, some woman was changing clothes... mildly said. "Ok, this is different culture, probably it is fine." And I continued reading.

While I was reading second chapter, some weird guy appeared. He didn't bother me, but went to other guys seated in front of me. He looked like a beggar, but weird. He was whispering something to other guys. They replied. Only thing I cathed was "You want cocain?". When he nodded and gave them money and recieved one white pill in return.

I haven't read third chapter there. I did quick computation and linear regression in my head. Only thing that could top the other would be shooting and I don't want to be there during shooting.

So I slowly walked to the Time square and played chess there. I have won and because of that world was beatiful. Even the guys in pose I would descripe as typical New York pose were bearable. Typical New York pose is when you are lying on the pavement and have one hand in your pants (not protecting your wallet thought, probably protecting something different).

Washington was also nice, we only didn't understand one thing, why is Capitol closed on Sunday. We spend a lot time in museums. They were free!

In Washington there are very nice and polite security guys. As we were falling asleep on various locations they only softly reminded us that we shloudn't sleep there. So if you weren't, you should go and sleep there in the park!


References

Presentations

Cool gif about isomorphism
Our first presentation
Our first presentation (Uncensored version)
My history presentation

Additional Information