19
votes
5answers
3k views
Erdos Conjecture on arithmetic progressions
Introduction:
Let A be a subset of the naturals such that $\sum_{n\in A}\frac{1}{n}=\infty$. The Erdos Conjecture states that A must have arithmetic progressions of arbitrary leng …
1
vote
3answers
526 views
A limit from an Erdos paper
Hi,
I need help to prove that, for $ N = \big\lfloor \frac{1}{2}n\log(n)+cn \big\rfloor $ with $c \in \mathbb R $ and $0 \leq k \leq n: $
$$ \lim_{n\rightarrow +\infty} \dbinom{ …
24
votes
3answers
1k views
Does there exist a comprehensive compilation of Erdos’s open problems?
Fan Chung and Ron Graham's book Erdos on Graphs: His Legacy of Unsolved Problems (A. K. Peters, 1998) collects together all of Erdos's open problems in graph theory that they could …
2
votes
0answers
408 views
Paul Erdős and Ramanujan Primes
It's easy to find Ramanujan's proof of Ramanujan primes:
Ramanujan's Proof
Wikipedia mentions that Paul Erdős also had a proof:
Wikipedia article on Bertrand's Postulate
Doe …
3
votes
3answers
615 views
Erdos distance problem n=12
The recent paper On the Erdos distinct distance problem in the plane
Authors: Larry Guth, Nets Hawk Katz prodded me to get a non-trivial example. Here is what I cannot find: and …
11
votes
2answers
623 views
Did Erdős publish his proof of the multiplicative version of the Erdős-Turán conjecture?
I read in an article of Erdős ("Extremal problems in number theory") that he had a proof of the multiplicative version of the Erdős-Turán conjecture. The statement of this theorem …
7
votes
6answers
2k views
If Erdős is published as Erdös in a paper, which do I cite?
There seems to be a few papers around with Erdős written as Erdös. For example:
MR0987571 (90h:11090) Alladi, K.; Erdös, P.; Vaaler, J. D. Multiplicative functions and small divi …
4
votes
1answer
357 views
Degree reduction argument in Guth-Katz’sproof of Erdos distinct distance problem in the plane
In the middle of page 9 of
http://arxiv.org/PS_cache/arxiv/pdf/1011/1011.4105v1.pdf.
They said " Now we select a random subset....choosing lines independently with
probability $\ …
2
votes
2answers
296 views
Determining the vector space for application of Cauchy Schwarz
In the paper "On the Erdős distinct distance problem in the plane" by Larry Guth and Nets Hawk Katz,
http://arxiv.org/PS_cache/arxiv/pdf/1011/1011.4105v1.pdf
they define the func …
3
votes
1answer
432 views
A question about the number of intersections of lines in $R^{3}$
Suppose I have n lines in $R^{3}$ with the conditions that: no 3 lines in one plane, no 3 lines intersect at one point, for fixed 2 lines, no 3 lines intersect these 2 lines at th …
3
votes
1answer
587 views
A limit involving the totient function
P. Erdős and Leon Alaoglu proved in [1] that for every $\epsilon > 0$ the inequality $\phi(\sigma(n)) < \epsilon \cdot n$ holds for every $n \in \mathbb{N}$, except for a set of …

