Mathematics Problem Archive
Furstenberg–Zimmer Structure Theorem
v1.3 research notesOver $\mathsf{RCA}_0$, does the Furstenberg–Zimmer structure theorem imply $\Pi^1_1\text{-}\mathsf{CA}_0$?...
Well-Ordered Linearizations
v1.3 research notesOver $\mathsf{RCA}_0$, is $\mathsf{EXT}(\omega^*)$ — the assertion that every well-founded partial order has a well-ordered linearization — equivalent...
Reverse Mathematics of Fraïssé's Conjecture
v1.3 research notesOver $\mathsf{RCA}_0$, is Fraïssé's conjecture for countable linear orders equivalent to $\mathsf{ATR}_0$?...
Lengths of Bounded-Rank Linear-Order WQOs
v1.3 research notesFor an ordinal $\alpha$, determine the length (maximal order type) of the well-quasi-order $L_\alpha$ of countable linear orders of Hausdorff rank bel...
Strengths of Laver and Nash–Williams BQO Theorems
v1.3 research notesDetermine the reverse-mathematical strengths of Laver's labeled-linear-order theorem $\mathsf{LAV}$ and the Nash–Williams bqo transfinite-sequence the...
Three-Element Better-Quasi-Order
v1.3 research notesIs there a subsystem weaker than $\mathsf{ATR}_0$ that proves that the three-element antichain is a better-quasi-order?...
Weak Infinitary Comprehension versus Weak Choice
v1.3 research notesIs weak-$L_{\omega_1,\omega}$-$\mathsf{CA}$ equivalent to weak-$\Sigma^1_1$-$\mathsf{AC}_0$?...
Open Mapping Theorem for Separable Banach Spaces
v1.3 research notesIs the open mapping theorem for separable Banach spaces provable in $\mathsf{RCA}_0$, or at least in $\mathsf{WKL}_0$?...
Strength of the Krein–Šmulian Theorem
v1.3 research notesDetermine the exact reverse-mathematical strength of the Krein–Šmulian theorem for separable Banach spaces....
Strength of Szemerédi's Theorem
v1.3 research notesIs Szemerédi's theorem provable in $\mathsf{ACA}_0$? More generally, determine its reverse-mathematical strength....
Ramsey's Theorem for Triples over a Weak Base
v1.3 research notesOver $\mathsf{RCA}^*_0$, is Ramsey's theorem for triples equivalent to $\mathsf{ACA}_0$, as it is over $\mathsf{RCA}_0$?...
Soft Phases in Two-Dimensional O(N) Models
v1.3 research notesDo spin correlations in the classical Heisenberg model, and other $O(N)$ models with $N>2$, decay exponentially at every nonzero temperature, or do th...
Long-Range Order for the Quantum Heisenberg Model
v1.3 research notes(A) Prove long-range order for the quantum Heisenberg ferromagnet in dimension $D>2$ at temperature $T>0$. (B) Prove long-range order for spin $1/2$ i...
Extended States with Extensive Disorder
v1.3 research notesEstablish, in some energy range, the existence of extended eigenstates or continuous spectrum for linear operators with extensive disorder, such as a ...
One-Dimensional Fermi Gas with Attractive Interaction
v1.3 research notesDetermine the large-distance behavior of the one-particle reduced density matrix for a one-dimensional Fermi gas with spin and attractive interaction....
Entropy Production in Nonequilibrium Statistical Mechanics
v1.3 research notesGive a fundamental and experimentally accessible definition of the entropy creation rate for general classical systems in stationary nonequilibrium st...
Optimal Flux for the Quarter-Filled Band
v1.3 research notesFor the two-dimensional square-lattice model of independent electrons at density $1/4$, does magnetic flux $\pi/2$ per plaquette minimize the ground-s...
Bose-Einstein Condensation in Continuum Models
v1.3 research notesProve that Bose-Einstein condensation occurs in a continuum model of a weakly interacting Bose gas, or determine whether the long-held assertion fails...
Meaning and Impossibility of Exact Helium Energy Levels
v1.3 research notesGive a mathematically precise meaning to determining the energy levels of the helium atom exactly, in the sense that hydrogen energy levels are exact,...
Extended States in the Anderson Model
v1.3 research notesProve that the Anderson model has purely absolutely continuous spectrum in dimension $\nu\geq 3$, for suitable disorder width $b-a$, in some energy ra...
Localization in Two Dimensions
v1.3 research notesProve that the spectrum of the Anderson model in dimension $\nu=2$ is dense pure point....
Quantum Diffusion in the Anderson Model
v1.3 research notesFor the Anderson model in dimension $\nu\geq3$ and disorder strengths $|b-a|$ admitting absolutely continuous spectrum, prove that $\sum_{n\in\mathbb ...
Absolutely Continuous Spectrum Under a Weighted L2 Condition
v1.3 research notesLet $V$ be a function on $\mathbb R^\nu$, $\nu\geq2$, satisfying $\int |x|^{-\nu+1}|V(x)|^2\,d^\nu x<\infty$. Prove that $-\Delta+V$ has absolutely co...
Bounded Excess Electrons
v1.3 research notesFor the $N$-electron Coulomb Hamiltonian with nuclear charge $Z$, let $N_0(Z)$ be the least $N$ after which adding electrons no longer lowers the grou...
Asymptotics of Atomic Ionization Energy
v1.3 research notesFor the $N$-electron Coulomb ground-state energy $E(N,Z)$, determine the asymptotics of the ionization energy $\delta E(Z)=E(Z,Z-1)-E(Z,Z)$ as $Z\to\i...
First-Principles Molecular Configurations
v1.3 research notesGive a mathematically rigorous justification of the techniques used to determine molecular configurations from first principles....
Continuity of the Integrated Density of States
v1.3 research notesProve that the integrated density of states $k(E)$ is continuous as a function of the energy $E$....
One-Dimensional Lieb-Thirring Constants
v1.3 research notesFor spatial dimension $\nu=1$ and $1/2<\gamma<3/2$, determine the optimal constants $L_{\gamma,1}$ in the Lieb-Thirring inequality as predicted by the...
Riemann-Hilbert Problem with non-analytic data
v1.3 research notesIn many situations one is concerned with the asymptotic behavior of Riemann-Hilbert problems with exponentially varying data of the form $e^{in\phi(z)...
Painlev\'e equations
v1.3 research notesWhat I have in mind here is not a specific problem, but a project, a very large scale project. The six (nonlinear) Painlev\'e equations form the core ...
Multivariate analysis
v1.3 research notesRandom matrix theory was introduced into theoretical physics by Wigner in the 1950s in his study of neutron scattering resonances, but as a subject, R...
Non-self adjoint spectral problems
v1.3 research notesMuch is now known, theoretically and also numerically, about the spectrum of self-adjoint operators. This is in great contrast to the situation regard...
Long-time behavior with non-generic initial data
v1.3 research notesThe long-time behavior of the solution of the Cauchy problem for a great many integrable systems on the line is now well-understood, using, for exampl...
The parking problem
v1.3 research notesA number of so-called ``transportation'' problems have now been analyzed in terms of RMT. These include: the ``vicious'' walker problem of M. Fisher, ...
The Toda lattice with random initial data
v1.3 research notesLet $J$ be a random tridiagonal matrix drawn from the tridiagonal Gaussian orthogonal ensemble and evolve it by the finite nonperiodic Toda flow, so i...
Perturbation theory for infinite dimensional integrable systems
v1.3 research notesThe bijective mapping properties of the scattering transform for a variety of integrable systems on the line between appropriate weighted Sobolev spac...
Perturbation theory for exactly solvable combinatorial problems
v1.3 research notesThe asymptotic behavior of a variety of combinatorial problems has now been analyzed in great detail. Here we have in mind Ulam's problem for the leng...
Initial/boundary value problems for integrable systems
v1.3 research notesIn the late 1990s Fokas introduced a new, more flexible approach to inverse scattering theory, and in recent years a number of researchers (Fokas, Its...
Multi-matrix models and models with an external field
v1.3 research notesThere has been considerable progress (Kuijlaars,...) in understanding basic statistics such as the correlation functions for the 2-matrix random matri...
numerical computation with random data
v1.3 research notesStandard algorithms to compute the eigenvalues of a random matrix $H$ are completely integrable Hamiltonian systems (see ). The question raised in was...
Mutually Unbiased Bases in Dimension Six
v1.3 research notesConstruct a set of at least four mutually unbiased bases in dimension six, or prove that there are no seven mutually unbiased bases in $\mathcal{H}_6$...
O3 — Finding a prime above a bound
v1.3 research notesGiven $n\in\mathbb{N}$, can a prime $p>n$ be found in deterministic polynomial time?...
O4 — Finding a prime in an arithmetic progression
v1.3 research notesGiven coprime $a,n\in\mathbb{N}$, can a prime $p\equiv a\pmod n$ be found in deterministic polynomial time?...
O5a — Deterministic polynomial-time integer factorization
v1.3 research notesIs complete integer factorization $C_5$ in deterministic polynomial time $P$?...
O5b — Randomized polynomial-time integer factorization
v1.3 research notesIs complete integer factorization $C_5$ in randomized polynomial time $R$?...
O6 — Factoring a positive-density set of integers
v1.3 research notesDoes 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...
O7a — Computing the squarefree part
v1.3 research notesGiven $n$, can one find $r,s\in\mathbb{N}$ with $n=r^2s$ and $s$ squarefree in deterministic polynomial time?...
O7b — Factoring from a squarefree-part oracle
v1.3 research notesIs complete integer factorization randomized polynomial-time reducible to computation of the squarefree part?...
O8 — Deterministic polynomial-time squarefreeness testing
v1.3 research notesCan one decide in deterministic polynomial time whether an integer $n$ is squarefree?...
O9 — Counting distinct prime factors
v1.3 research notesCan $\omega(n)$, the number of distinct prime factors of $n$, be computed in deterministic polynomial time?...