Unsolved Problems
Showing 1-27 of 27 problems
Sums of Smooth Numbers
Is every $n \leq N$ the sum of two integers, all of whose prime factors are at most $N^\varepsilon$?...
Sumsets of Perfect Squares
Is there an absolute constant $c > 0$ such that if $A \subset \mathbb{N}$ is a set of squares of size at least 2, then $|A + A| \geq |A|^{1+c}$?...
Products of Primes Modulo p
Let $p$ be a large prime, and let $A$ be the set of all primes less than $p$. Is every $x \in \{1, \dots, p-1\}$ congruent to some product $a_1a_2$ mo...
Multiplicatively Closed Set Density
Let $A$ be the smallest set containing 2 and 3, and closed under the operation $a_1a_2 - 1$ (if $a_1, a_2 \in A$, then $a_1a_2 - 1 \in A$). Does $A$ h...
Gaps Between Sums of Two Squares
Is there always a sum of two squares between $X - \frac{1}{10}X^{1/4}$ and $X$?...
Waring's Problem Over Finite Fields
Determine bounds for Waring's problem over finite fields....
Irreducibility of Random {0,1} Polynomials
Is a random polynomial with coefficients in $\{0, 1\}$ and nonzero constant term almost surely irreducible?...
Bounds for Birch's Theorem
Let $d \geq 3$ be odd. Give bounds on $\nu(d)$ such that if $n > \nu(d)$ then any homogeneous polynomial $F(\mathbf{x}) \in \mathbb{Z}[x_1, \dots, x_n...
Solutions to Polynomial Equations in Dense Sets
Finding a single solution to $F(x_1, \dots, x_n) = C$ can be very difficult. What conditions on $A$ ensure that the number of solutions in $A$ is roug...
Maximal Covering Interval
What is the largest $y$ for which one may cover the interval $[y]$ by residue classes $a_p \pmod p$, one for each prime $p \leq x$?...
Bounds for Homogeneous Polynomial Zeros
Let $d \geq 3$ be an odd integer. Give bounds on $\nu(d)$ such that if $n > \nu(d)$ the following is true: given any homogeneous polynomial $F(\mathbf...
Polynomial Solutions in Dense Sets
Finding a single solution to a polynomial equation $F(x_1, \dots, x_n) = C$ can be very difficult. What conditions on $A$ ensure that the number of su...
Congruent Products of Consecutive Numbers
What is the least prime $p$ such that there are integers $a, k_1, k_2, k_3$ with $\prod_{i=1}^{k_1} (a+i) \equiv \prod_{i=1}^{k_2} (a+k_1+i) \equiv \p...
Cohen-Selfridge Problem on $\pm p^a \pm 2^b$
What is the least positive odd number not of the form $\pm p^a \pm 2^b$, where $p$ is an odd prime?...
Erdős Problem #952
Is there an infinite sequence of distinct Gaussian primes $x_1,x_2,\ldots$ such that $ \lvert x_{n+1}-x_n\rvert \ll 1? $ ...
Lonely runner conjecture
Conjecture Suppose $k$ runners having distinct constant speeds start at a common point and run laps on a circular track with circumference 1. Then for...
Chowla's cosine problem
Problem Let $A \subseteq {\mathbb N}$ be a set of $n$ positive integers and set $$ m(A) = - \min_x \sum_{a \in A} \cos(ax). $$ What is $m(n) = \min_A...
Quartic rationally derived polynomials
Call a polynomial $p \in {\mathbb Q}[x]$ rationally derived if all roots of $p$ and the nonzero derivatives of $p$ are rational. Conjecture There doe...
Algebraic independence of pi and e
Conjecture $\pi$ and $e$ are algebraically independent...
Euler-Mascheroni constant
Question Is Euler-Mascheroni constant an transcendental number?...
Are all Fermat Numbers square-free?
Conjecture Are all Fermat Numbers $$ F_n = 2^{2^{n } } + 1 $$ Square-Free?...
Are there only finite Fermat Primes?
Conjecture A Fermat prime is a Fermat number $$ F_n = 2^{2^n } + 1 $$ that is prime. The only known Fermat primes are F_0 =3,F_1=5,F_2=17,F_3 =257,F_...
Are all Mersenne Numbers with prime exponent square-free?
Conjecture Are all Mersenne Numbers with prime exponent ${2^p-1}$ Square free?...
Sets with distinct subset sums
Say that a set $S \subseteq {\mathbb Z}$ has distinct subset sums if distinct subsets of $S$ have distinct sums. Conjecture There exists a fixed cons...
Odd incongruent covering systems
Conjecture There is no covering system whose moduli are odd, distinct, and greater than 1....
Davenport's constant
For a finite (additive) abelian group $G$, the Davenport constant of $G$, denoted $s(G)$, is the smallest integer $t$ so that every sequence of elemen...
Snevily's conjecture
Conjecture Let $G$ be an abelian group of odd order and let $A,B \subseteq G$ satisfy $|A| = |B| = k$. Then the elements of $A$ and $B$ may be ordered...