Mathematics Problem Archive

Can the sequence of metric balls in an infinite Cayley graph form a family of expanders?...

For a graph sequence $(G_n)$ define $e((G_n))=\liminf |E(G_n)|/|V(G_n)|$, and define its combinatorial cost as the infimum of $e((H_n))$ over graph se...

Compactness implies that for every $\varepsilon>0$ there is $K>0$ such that every finite graph can be approximated within error $\varepsilon$ by a fin...

Which probability measures can occur as eigenvalue distributions of finite $d$-regular graphs? Find natural restrictions....

Do uniformly random $d$-regular graphs converge, in local-global convergence, to the weak closure of independent identically distributed processes?...

Is the i.i.d. action of the free group $F_2$ a local-global limit of finite actions of $F_2$?...

Can every ergodic unimodular random network that is almost surely an infinite tree be obtained as the limit of an expander family?...

Let $G$ be an infinite vertex-transitive graph, let $A$ be a finite vertex set, let $b$ be a vertex, and let $\partial A$ be the set of vertices at di...

Define the first $L^2$ Betti number of a vertex-transitive graph $G$ from the expected degree of a free spanning forest. Do $G$ and its square $G^2$ h...

Does every infinite Cayley graph, or every infinite vertex-transitive graph, have a spanning tree without leaves?...

In every infinite Cayley graph, does the density of dead ends tend to zero?...

Are factors of i.i.d. on the $3$-regular tree closed in the weak topology? In particular, is the weak limit of majority functions on $n$-balls a facto...

For every $k>1$, does there exist $C(k)<1$ such that the return probability of every transient $k$-regular Cayley graph is at most $C(k)$?...

Let $(G_n)$ and $(H_n)$ converge to the same graph limit, and let $(T_n)$ be a convergent sequence with each $T_n$ a spanning tree of $G_n$. Do there ...

Let $G$ be a bounded-degree expander, or strongly ergodic, graphing that can be properly colored by $C$ colors with arbitrarily small error. Can it be...

Is there a polynomial time algorithm that is able to find the largest clique of $G$ (with high probability) for $\omega \ll \sqrt{n}$ ? For example, f...

Given a visibility graph $G$ and a Hamiltonian circuit $C$, determine in polynomial time whether there is a simple polygon whose vertex visibility gra...

Does every simple graph with maximum vertex degree $\Delta \leq 6$ have a 3D orthogonal point-drawing with no more than two bends per edge? A 3D ortho...

Babai's problem: which groups are Babai invariant groups?...

Given $n\in\mathbb{N}$, can a prime $p>n$ be found in deterministic polynomial time?...

Given coprime $a,n\in\mathbb{N}$, can a prime $p\equiv a\pmod n$ be found in deterministic polynomial time?...

Is complete integer factorization $C_5$ in deterministic polynomial time $P$?...

Is complete integer factorization $C_5$ in randomized polynomial time $R$?...

Does there exist a set $S\subset\mathbb{N}$ of positive lower asymptotic density for which complete factorization of every input $n\in S$ is in determ...

Given $n$, can one find $r,s\in\mathbb{N}$ with $n=r^2s$ and $s$ squarefree in deterministic polynomial time?...

Is complete integer factorization randomized polynomial-time reducible to computation of the squarefree part?...

Can $\omega(n)$, the number of distinct prime factors of $n$, be computed in deterministic polynomial time?...

Can one decide in deterministic polynomial time whether a coprime integer $a$ is a square modulo a composite $n$?...

Is complete integer factorization randomized polynomial-time reducible to deciding quadratic residuosity modulo a composite?...

Given a prime $p$, can a quadratic nonresidue modulo $p$ be found in deterministic polynomial time?...

Given a sign vector $\varepsilon\in\{-1,1\}^k$, can the least prime $p$ satisfying $(p_i/p)=\varepsilon_i$ for every $i\le k$ be found in deterministi...

Given a prime $p$ and a quadratic residue $a$, can a square root $x^2\equiv a\pmod p$ be found in deterministic polynomial time?...

Given a prime $p$ and $f\in(\mathbb{Z}/p\mathbb{Z})[x]$ known to have a root, can a root be found in deterministic polynomial time?...

Given a prime $p$ and $f\in(\mathbb{Z}/p\mathbb{Z})[x]$, can the complete irreducible factorization of $f$ be found in deterministic polynomial time?...

Given a prime $p$ and $b$, can one decide in deterministic polynomial time whether $b$ generates $(\mathbb{Z}/p\mathbb{Z})^*$?...

Is recognition of primitive roots modulo a prime in randomized polynomial time $R$?...

Given a prime $p$, can a generator of $(\mathbb{Z}/p\mathbb{Z})^*$ be found in deterministic polynomial time?...

Given a prime $p$ and $a$ coprime to $p$, can $\operatorname{ord}_p(a)$ be computed in deterministic polynomial time?...

Given a prime $p$ and elements $g,b$ with $b$ in the subgroup generated by $g$, can an exponent $x$ satisfying $g^x\equiv b\pmod p$ be found in determ...

Given $g,b,n$ such that $g^x\equiv b\pmod n$ has a solution, can such an exponent $x$ be found in deterministic polynomial time?...

Given $k,m,n$ with odd $n$ and $\gcd(km,n)=1$, can integers $x,y$ satisfying $x^2-ky^2\equiv m\pmod n$ be found in deterministic polynomial time?...

Is discrete logarithm modulo a prime randomized polynomial-time reducible to computing $g^{xy}$ from $g,g^x,g^y$?...

Given a prime $p$ and $n$, can one construct in deterministic polynomial time an elliptic curve over $\mathbb{F}_p$ having exactly $n$ points whenever...

Given an elliptic curve over $\mathbb{F}_p$ and points $P,Q$ such that $P=nQ$ for some $n$, can such an $n$ be found in deterministic polynomial time?...

Can one decide in deterministic polynomial time whether $x^2-dy^2=-1$ has an integral solution?...

Is there an absolute upper bound for the size of a rational Diophantine $m$-tuple, a set of nonzero rationals for which the product of every two disti...

For each $n\in\{-3,3,5,8,12,20\}$, prove that no set of four distinct positive integers has property $D(n)$, meaning that every pairwise product plus ...

Let $U$ be the set of integers $n\not\equiv2\pmod4$ for which there are at most two distinct $D(n)$-quadruples. Is $U$ finite?...

For every nonzero integer $n$ that is not a square, are there only finitely many $D(n)$-quadruples?...

Are there infinitely many Diophantine triples that are also $D(n)$-triples for three distinct integers $n\ne1$?...