Fixed-point theorem (Wikipedia).
Brouwer Fixed-point theorem (Wikipedia).
q-Harmonic Series.
Harmonic Series (Wikipedia).
Meromorphic function (Wikipedia).
Lacunary function (Wikipedia).
Root of unity (Wikipedia).
Root of unity modulo n (Wikipedia).
Gaussian Moat (Wikipedia).
Partition problem (Wikipedia).
Korf, Richard E. (2009). Multi-Way Number Partitioning (PDF).
Lambert Summation (Wikipedia).
Generating function (Wikipedia).
Coins in a fountain problems (Wikipedia).
Writing Mathematics Effectively (by Eric Rowland, pdf).