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
101
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

63
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

22
List of interesting integrals for early calculus students
math.stackexchange.com

21
The coupon collector's earworm
mathoverflow.net

19
Cauchy-Schwarz and pigeonhole
mathoverflow.net

18
What are your favorite instructional counterexamples?
mathoverflow.net

17
Picking random points in the volume of sphere with uniform probability
math.stackexchange.com

17
Splitting Pythagorean triples
mathoverflow.net

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

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

13
A strange sum over bipartite graphs
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

11
Concentration bounds for sums of random variables of permutations
mathoverflow.net

10
Motivation for spectral graph theory.
math.stackexchange.com

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

9
Sets A such that A+A contains the largest set [0,1,..,t]
mathoverflow.net

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

9
Non trivial colouring of the edges of an infinite complete graph
mathoverflow.net

9
Average Length of Longest Palindromic Subsequence
math.stackexchange.com

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

8
Undergraduate Level Math Books
mathoverflow.net

8
Bound on cardinality of a union
mathoverflow.net

8
Predator and Prey
math.stackexchange.com

8
Best lower bound for off-diagonal Ramsey numbers
mathoverflow.net

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

8
Concentration results for inner products of two independent random gaussian vectors
mathoverflow.net

8
Matching with probabilistic edges
mathoverflow.net

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