组合学
- What does it mean to choose 1/2 out of n/2 ? Or out of n?
Combinatorial Gardens
- Mahonian distribution - the number of inversions in a permutation of a multiset...
Combinatorics - Gian-Carlo Rota
- He worked on the theory of incidence algebras (which generalize the 19th-century theory of Möbius inversion) and popularized their study among combinatorialists, set the umbral calculus on a rigorous foundation, unified the theory of Sheffer sequences and polynomial sequences of binomial type, and worked on fundamental problems in probability theory.
- His series of ten papers on the "Foundations of Combinatorics" in the 1960s is credited with making it a respectable branch of modern mathematics.
- Crapo, Rota. On The Foundations of Combinatorial Theory: Combinatorial Geometries.
Twelvefold way
Combinatorial principles
- Rule of sum
- Rule of product
- Inclusion-exclusion principle
- Rule of division
- Bijective proof
- Double counting
- Pigeonhole principle
- Method of distinguished element
- Generating function
- Recurrence relation