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 not deleted user 43954

Prime numbers, diophantine equations, diophantine approximations, analytic or algebraic number theory, arithmetic geometry, Galois theory, transcendental number theory, continued fractions

10 votes

Dividing a cake between $n-1$, $n$, or $n+1$ guests

Proposition. $f(n)\ge 2n+\tfrac 13\left(\sqrt{\tfrac{n}3+1}-2\right) $ for any natural $n\ge 13$. Proof. Fix the cake cutting with the minimum number $f=f(n)$ of slices. We shall work with the graph $ …
Alex Ravsky's user avatar
  • 5,409
5 votes
Accepted

Congruential equidistribution, prime numbers, and Goldbach conjecture

If $S$ is congruentially equidistributed and contains enough elements .... is it true that $S+S$ contains all the positive integers except a finite number of them? Let $S=\bigcup_{n=1}^\infty \{2^{2 …
Alex Ravsky's user avatar
  • 5,409
4 votes

Is there a non-trivial topological group structure of $\mathbb{Z}$?

There is a huge number of such topologies. Let $G$ be any discrete abelian group. By $\widehat G$ we denote the family (in fact, a group) of its characters, that is of homomorphisms from $G$ to the un …
Alex Ravsky's user avatar
  • 5,409
2 votes

Smith normal form and last invariant factor of certain matrices

To mark the question answered, I copied below my accepted answer from Mathematics Stack Exchange. There are no matrices $M_1$ and $M_2$ which you are trying to find because of the following propositio …
Alex Ravsky's user avatar
  • 5,409
2 votes
Accepted

Is this approximation for $\pi$ enough to make this value converge? And how to find an upper...

For each nonnegative integer $n$ we have $$I_n-J_n=\sum_{k=0}^n \frac{a_k}{\ln^{k+1}(\pi)} ( \pi p_k(\ln\pi) - k! )-\sum_{k=0}^n \frac{a_k}{\ln^{k+1}(\pi)} ( S_n p_k(\ln\pi) - k! )=$$ $$(\pi-S_n)\sum_ …
Alex Ravsky's user avatar
  • 5,409
2 votes

Does $n(H_n-H_{n-n^k})\colon k\in[0,1)$ span the set $O(nH_n)-O(n)$

For each natural $n$ we have $$f(n)=\left(1-\frac{1}{n}\right)^{g(n)}=\left(\left(1-\frac{1}{n}\right)^{n}\right)^{g(n)/n}.$$ Since $\lim_{n\to\infty} \left(1-\frac{1}{n}\right)^{n}=\frac 1e$, the bou …
Alex Ravsky's user avatar
  • 5,409
2 votes

Square roots and prime numbers

GH from MO's answer suggests to study (odd) composite numbers $m$ such that $\sigma_2(m)−1$ is a square. Therefore $\sigma_2(m)$ is not divisible by $4$ and has no (prime) divisors equal $3$ modulo $4 …
Alex Ravsky's user avatar
  • 5,409
1 vote

Existence of a zero-sum subset

There is a special version of this question (for $n=15$ and $m\le 7$) at Mathematics.SE. For each $n\ge 2$ I constructed a set $S$ with the property requiring $m\ge \left\lfloor\tfrac n2\right\rfloor= …
Alex Ravsky's user avatar
  • 5,409
1 vote

Can we balance $2$-powers?

Fedor Petrov's comment shows than for each $k$ there are only finitely many cases for $x_1$ to check, so I wrote a program to do this. The positive answer is already obtained for all natural $k\le 10$ …
Alex Ravsky's user avatar
  • 5,409
0 votes
Accepted

If $p^k m^2$ is an odd perfect number with special prime $p$, then $p^k < 2am$ for some posi...

Since $p^k<m^2$, we have $p^k<2(m−1)m$, and so we can put $a=m−1$.
Alex Ravsky's user avatar
  • 5,409