Stack Exchange

Kevin P. Costello

Riverside, CA

http://www.math.ucr.edu/~costello

Currently an Assistant Professor at UC-Riverside. Interested in Combinatorics, Probability, and especially in their intersection.
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Top Questions
Top Answers
97
If you break a stick at two points chosen uniformly, the probability the three resulting sticks form a triangle is 1/4. Is there a nice proof of this?
mathoverflow.net

59
Tweetable Mathematics
mathoverflow.net

31
What's a nice argument that shows the volume of the unit ball in $\mathbb R^n$ approaches 0?
mathoverflow.net

21
The coupon collector's earworm
mathoverflow.net

20
List of interesting integrals for early calculus students
math.stackexchange.com

18
Cauchy-Schwarz and pigeonhole
mathoverflow.net

16
Picking random points in the volume of sphere with uniform probability
math.stackexchange.com

16
Splitting Pythagorean triples
mathoverflow.net

15
What are your favorite instructional counterexamples?
mathoverflow.net

14
Number of invertible {0,1} real matrices?
mathoverflow.net

13
A strange sum over bipartite graphs
mathoverflow.net

13
What are some good examples of non-monotone graph properties?
mathoverflow.net

12
How many random sieve operations to decimate the set {2,…,n}?
mathoverflow.net

12
Parameterized complexity from P to NP-hard and back again
cstheory.stackexchange.com

10
Invertibility of a certain matrix indexed by the Hamming cube
mathoverflow.net

9
Full-rank rectangular matrices over GF(2)
mathoverflow.net

9
Maximum value $c$ s.t. $\exists$ a subset $S$ of $\{z_1,z_2,\ldots,z_n\}$ s.t. $\left|\sum_{z\in S}z\right|\geq c$ ($\sum_{i=1}^{n}|z_i|=1$).
math.stackexchange.com

9
Motivation for spectral graph theory.
math.stackexchange.com

8
On the invertibility of the adjacency matrix of a graph
math.stackexchange.com

8
Szemerédi's Regularity Lemma
math.stackexchange.com

8
Average Length of Longest Palindromic Subsequence
math.stackexchange.com

8
Predator and Prey
math.stackexchange.com

8
Undergraduate Level Math Books
mathoverflow.net

8
Bound on cardinality of a union
mathoverflow.net

8
Non trivial colouring of the edges of an infinite complete graph
mathoverflow.net

8
How to efficiently sample uniformly from the set of p-partitions of an n-set?
mathoverflow.net

8
Matching with probabilistic edges
mathoverflow.net

8
Concentration bounds for sums of random variables of permutations
mathoverflow.net

8
Sets A such that A+A contains the largest set [0,1,..,t]
mathoverflow.net

7
Best lower bound for off-diagonal Ramsey numbers
mathoverflow.net

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