Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options answers only not deleted user 11142

Asymptotic behavior of functions, asymptotic series and related topics

2 votes

Asymptotic expression for $j$ which satisfies $\binom{n}{j}/j! \sim k$ as $n\to\infty$

If you take logs of both sides, and expand the left hand side in a power series around infinity (to first order), you get: $$\frac{\frac{j}{2}-\frac{j^2}{2}}{n}+j \left(-2 \log (j)-\log \left(\fra …
Igor Rivin's user avatar
  • 96.4k
3 votes

Asymptotic of the sum of squared primes

By the prime number theorem, the number of primes between $N/2$ and $N$ is on the order of $N/\log N.$ So, the sum of just those primes squared is of order $N^3/ \log N.$
Igor Rivin's user avatar
  • 96.4k
0 votes

Is Laplace's method applicable to this integral?

Mathematica tells us that the principal value can be evaluated in closed form thus: $$e^{-A} 2^{-A N+B-1} \left((-1)^{A N-B+1} \Gamma (-B+A N+1) \Gamma (B-A N,-A)-i \pi \right).$$ (OK, the $i \pi …
Igor Rivin's user avatar
  • 96.4k
3 votes

Asymptotics of Generating Functions

I don't really understand the significance of your example, but the univariate version of the question is covered very thoroughly in Flajolet-Sedgewick's Analytic Combinatorics, while the (much harder …
Igor Rivin's user avatar
  • 96.4k
6 votes
Accepted

Connected graphs that are not 2 connected

See Kemkes, Graeme; Sato, Cristiane M.; Wormald, Nicholas, Asymptotic enumeration of sparse $2$-connected graphs, Random Struct. Algorithms 43, No. 3, 354–376 (2013). Zbl 1273.05127. PDF and referen …
Igor Rivin's user avatar
  • 96.4k
4 votes

Growth of powers of non-negative integer matrices

I am not sure I understand the question. Any matrix $A$ (integer or not, positive or not) has a Jordan canonical form $A = MJM^{-1},$ whereupon $A^n = M J^n M^{-1}.$ If $A$ is integer and nonsingular, …
Igor Rivin's user avatar
  • 96.4k
1 vote

Asymptotics of Fourier coefficients of power-type functions

This is a cosine transform of $t^{-a} \mathbb{1}[0, 1],$ which can be evaluated explicitly using the trusty mathematica, which gives: $ \frac{t^{a+1} \, _1F_2\left(\frac{a}{2}+\frac{1}{2};\frac{1}{ …
Igor Rivin's user avatar
  • 96.4k
0 votes

Semiclassical expansions of eigenvalues of Schrödinger operators

If you look at: Microlocal WKB expansions by A. Martinez (available through cite seer), you will see that this is a fairly popular subject, where many results have been obtained by Sjostrand et al.
Igor Rivin's user avatar
  • 96.4k
4 votes

Asymptotic number of invertible matrices with integer entries

(the authors were unaware of Newman's work), with full asymptotics, and in a companion paper, a "softer" result was derived by Eskin and McMullen by ergodic-theoretic methods in the very well-known paper …
Igor Rivin's user avatar
  • 96.4k
1 vote

Asymptotic expansion of a sequence given by an integral with reciprocal Gamma function

I am not sure about the asymptotic expansion, but approximating $1/\Gamma(x-1)$ by $x$ near $0$ (and $1/(1-x)$ near $1$) does show that the decrease is faster than $1/\log n$ - the integral of $x n^{x …
Igor Rivin's user avatar
  • 96.4k
4 votes

What is the probability that two random permutations have the same order?

That the probability is at least $O(1/n^2)$ is immediate, since the probability that both permutations are $n$-cycles is $1/n^2.$ For the upper bound, there is a convergence speed estimate by Zacharov …
Igor Rivin's user avatar
  • 96.4k
3 votes
Accepted

Asymptotic behaviour/upper bound for $\int_0^{\infty} \exp(-c x^a+K x^b)dx$ for $a>b>0$ as $...

.$ I leave the final computation of the asymptotics to the interested reader. EDIT Actually, this is not quite Watson's lemma. …
Igor Rivin's user avatar
  • 96.4k
1 vote

A distribution related to Fermat's two squares theorem

Following Fedor Petrov's comment: the arguments of Gaussian primes are known to be uniformly distributed, see Example 7.20 in Number theory: an introduction to class field theory by Kato et al (2000). …
Igor Rivin's user avatar
  • 96.4k
0 votes

Bound on sum of complex summands involving binomial coefficients

{y}\right)}{y} $$ Since the middle binomial coefficient is approximately $4^n/\sqrt{n},$ that cancels the $(xy)^n$ term (under your assumption) leaving the $1/\sqrt{n}$, so you just need to check the asymptotics
Igor Rivin's user avatar
  • 96.4k
3 votes

does this sum have a limit?

Not an answer. First, Mathematica says that $$a_n = \frac{-4 n \, _2F_1\left(\frac{1}{2},-n-1;-4 n;2\right)+n \, _2F_1\left(\frac{3}{2},-n;1-4 n;2\right)+\, _2F_1\left(\frac{3}{2},-n;1-4 n;2\ri …
Igor Rivin's user avatar
  • 96.4k

15 30 50 per page