- One of the greatest explanations of “Congruence Modulo n” I have ever come across can be found here, this paper is written by Tong Qiu (tq7bw) .
- Detailed doc on solving recurrence relations can be found here.
- A succinct proof of Kuratowski’s theorem, can be found here, its written by Mary Radcliffe.
- Nice and compact Graph Theory lectures: http://compalg.inf.elte.hu/~tony/Oktatas/TDK/FINAL/
- http://compalg.inf.elte.hu/~tony/ , this page has almost everything about graph theory, especially this book which contains all the theorems of elementary graph theory along with their rigorous proofs. The site is in Hungarian, but even randomly clicking any link brings up something interesting to read.
Homepage of some of the great Math professors
- http://home.golden.net/~randre/ , he has written a great book on Set Theory and its free of cost downloadable from his homepage.
- https://web.math.princeton.edu/~pds/ , Sir Paul Seymour, he has done so much in the field of graph theory and its apparent from his list of papers he has published and https://web.math.princeton.edu/~mchudnov/ , Maria Chudnovsky, Paul Seymour’s PhD student, her papers are very informative as well.
- CS W4205 – COMBINATORIAL ( Combinatorics for Computer Science) course homepage, it contains all the course material as well: http://www.cs.columbia.edu/~cs4205/ .
- Herbert Wilf, mine, gold mine of awesome papers: https://www.math.upenn.edu/~wilf/ .
- https://www.math.ucla.edu/~pak/ , Igor Pak, the amount of nice papers on any mathematical field you can find on his homepage, is too damn high.
- http://philosophyfaculty.ucsd.edu/faculty/ctolley/ Clinton Tolley, we can find good amount of philosophical/mathematical texts from his homepage, and http://philosophyfaculty.ucsd.edu/faculty/ctolley/texts/ is where we can find them.
- Andrew Ranicki, a very good pure math professor, he has written a lot of papers/books on various fields of pure math which can be found here.
- Fred Richman, first 101 interesting numbers.