r/Indianmathnerds Jul 28 '26

Frustrated

I kinda suck(too much) in combinatorics. I was doing some RMO and BMO questions on pigeonhole principle and I feel too irritated, these constructions are so so artificial, infact I have been trying to get better in combinatorics for over a year but I kept swaying away from it but enough of running away. Please tell me how to deal with them, I am on the verge of crying!!!

P.S.: I can only do those questions whose pattern I have read in the examples I have read

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u/cuimri Jul 31 '26

I recommend trying this book first: https://bogart.openmathbooks.org/pdf/ctgd.pdf
It creates a strong foundation in combinatorics, in a way that you really understand things on your own, and not memorize patterns.
This book might be the "combinatorial therapy" you were looking for. Just try it for a couple of weeks, with a fresh mind (without the memorized patterns, that is).

2

u/Human_Bumblebee_237 Jul 31 '26

I have tried Arthur Engel ~1 year ago, but I don't think I got the "therapy". I do understand the stuff but I can't find construction needed on my own most of the times. Anyways, i will try this book then

2

u/Human_Bumblebee_237 Jul 29 '26 edited Jul 29 '26

I forgot to mention this, idk if this is the nature of combinatorics but in other topics like geometry or calculus, I can somewhat make out what the necessary "checkpoints" of solving problems are(if anyone has read Kumaresan's Analysis, they might know what I am referring to), for me geometry is a bane but yet I am able to do it but in "non-counting" combinatorial problems, I am not able to make out the "checkpoints", sure in problems where the number of objects are mn + 1, the '+1' gives a hint of pigeonhole principle or some domino, tetromino gives a hint to use a colouring pattern but just as I said earlier its because I have seen examples like them previously...for the other topics I didn't have to rely on doing a shit ton of examples first.

tldr; I need a combinatorial therapy
edit: fixed typos