I worked with a few friends on writing a mini one-round puzzle hunt for this year's MOP students. If you want to play, you can do so now at the following URL: https://web.evanchen.cc/mop I'm not sure whether or not this is going to become a recurring tradition. On the one hand, it was loads of… Continue reading MOP 2021 puzzle hunt
Unnecessarily detailed stories of my Mystery Hunt puzzles
As a follow-up to the previous post, I am recording here some details about the (numerous, varied, and deep) revisions that a bunch of my puzzles went through during the production process. These puzzles are in chronological order of when I wrote the puzzle. Spoiler warning: Unlike the last post, these will completely spoil all… Continue reading Unnecessarily detailed stories of my Mystery Hunt puzzles
Some puzzle-writing thoughts from an amateur
The 2021 Mystery Hunt concluded a while ago, and wow, what an experience. I was lucky enough to be on the organizing team, and I am so proud right now to be able to say I am a ✈️✈️✈️ Galactic Trendsetter ✈️✈️✈️. (If you don't know what a puzzle hunt is, betaveros has a great… Continue reading Some puzzle-writing thoughts from an amateur
USEMO Problem Development, Behind the Scenes
In this post I'm hoping to say a bit about the process that's used for the problem selection of the recent USEMO: how one goes from a pool of problem proposals to a six-problem test. (How to write problems is an entirely different story, and deserves its own post.) I choose USEMO for concreteness here,… Continue reading USEMO Problem Development, Behind the Scenes
USA Special Team Selection Test Series for IMO 2021
A lot of people have been asking me how team selection is going to work for the USA this year. This information was sent out to the contestants a while ago, but I understand that there's a lot of people outside of MOP 2020 who are interested in seeing the TST problems :) so this… Continue reading USA Special Team Selection Test Series for IMO 2021
On choosing exercises
Finally, if you attempt to read this without working through a significant number of exercises (see §0.0.1), I will come to your house and pummel you with [Gr-EGA] until you beg for mercy. It is important to not just have a vague sense of what is true, but to be able to actually get your… Continue reading On choosing exercises
USEMO sign-ups are open
I'm happy to announce that sign-ups for my new olympiad style contest, the United States Ersatz Math Olympiad (USEMO), are open now! The webpage for the USEMO is https://web.evanchen.cc/usemo.html (where sign-ups are posted). The US Ersatz Math Olympiad is a proof-based competition open to all US middle and high school students. Like many competitions, its… Continue reading USEMO sign-ups are open
Circular optimization
This post will mostly be focused on construction-type problems in which you're asked to construct something satisfying property $latex {P}&fg=000000$. Minor spoilers for USAMO 2011/4, IMO 2014/5. 1. What is a leap of faith? Usually, a good thing to do whenever you can is to make ``safe moves'' which are implied by the property $latex… Continue reading Circular optimization
Meritocracy is the worst form of admissions except for all the other ones
I'm now going to say something explicitly that I hinted at in June: I don't think a student deserves to make MOP more because they had a higher score than another student. I think it's easy to get this impression because the selection for MOP is done by score cutoffs. So it sure looks that… Continue reading Meritocracy is the worst form of admissions except for all the other ones
MOHS hardness scale
There's a new addition to my olympiad problems and solutions archive: I created an index of many past IMO/USAMO/USA TST(ST) problems by what my opinions on their difficulties are. You can grab the direct link to the file below: https://evanchen.cc/upload/MOHS-hardness.pdf In short, the scale runs from 0M to 50M in increments of 5M, and every… Continue reading MOHS hardness scale
Power Overwhelming 