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Digests
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
31
votes
Why is the Derangement Probability so Close to $\frac{1}{e}$?
combinatorics
intuition
inclusion-exclusion
derangements
asked May 22 '13 at 18:21
math.stackexchange.com
9
votes
When does a pointwise CLT hold?
pr.probability
asked Nov 16 '09 at 20:09
mathoverflow.net
9
votes
When is the Subgroup Lattice Graded?
combinatorics
group-theory
finite-groups
order-theory
lattice-orders
asked Apr 4 '19 at 22:00
math.stackexchange.com
8
votes
Avoiding exactly one permutation pattern
combinatorics
reference-request
permutations
pattern-matching
asked Aug 24 '18 at 22:18
math.stackexchange.com
6
votes
Distribution of maximum proportion of heads in an infinite sequence of flips
probability-theory
probability-distributions
reference-request
asked May 19 '18 at 5:57
math.stackexchange.com
6
votes
Probability of unique winner in a coin flipping game (limit of a recursive sequence)
real-analysis
probability
recurrence-relations
asked Aug 8 '19 at 23:42
math.stackexchange.com
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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