Overview
This 40-minute mathematics video introduces Stirling numbers of the second kind, a lesser-known but fascinating combinatorial concept. Explore these numbers from basic identities to complex formulas, learning how to establish a recurrence relation, construct a Stirling triangle, and discover surprising connections to sums of products. The comprehensive tutorial progresses through multiple examples and proofs, including a demonstration of the general formula using strong induction and the application of the Sieve Theorem. Perfect for mathematics enthusiasts looking to expand their combinatorial knowledge beyond the more familiar binomial coefficients found in Pascal's triangle. The presentation includes detailed explanations with timestamps covering introductory concepts, basic identities, recurrence relations, counting surjections, and culminates with the complete formula derivation.
Syllabus
0:00 Intro
2:24 Meet the Stirlings
4:41 Basic Identities
6:40 n at least 2
7:48 4 subset 2
9:06 When k=2
10:09 The Recurrence
12:35 The Triangle
14:30 Counting Surjections
17:34 An hn,k Surprise
20:03 Proving a Spooky Claim
23:00 Induction Basis Step
25:40 Induction Step
27:23 General Formula
32:24 Sieve Example
34:31 Applying the Sieve
37:16 THE FORMULA!!!
39:22 Conclusion
Taught by
Wrath of Math