Number of k-subsets of an n-set: C(n,k) = n! / (k! (n-k)!). Entries of Pascal's triangle.
Combination C(n,k) = nCr
Related concepts
- Factorial n!
- Permutation P(n,k)
- Binomial theorem
- Inclusion-exclusion principle
- Catalan numbers C_n
- Ramsey's theorem
- Graph G = (V, E)
- Integer partition
- Stirling numbers of 1st/2nd kind
- Catalan numbers
- Szemerédi's theorem
- Erdős-Ko-Rado theorem
- Ramsey's theorem (finite/infinite)
- Matroid
- Sperner / LYM inequality
- Memristor: V = M(q)·i; HP 2008 model dx/dt = μ_V·R_on·i/D², 0≤x≤1
- Hantzsch-Widman heteroatom-replacement framework: standard prefix table (oxa/thia/aza) for monocyclic heterocycles
- BioBrick standard
- Glycosidic linkage combinatorics: 2 anomers × N positions isomers