Mathematics Problem Archive

Showing 2201-2250 of 3440 problems (Page 45 of 69)

AMR-074-0119
Open

Furstenberg–Zimmer Structure Theorem

v1.3 research notes

Over $\mathsf{RCA}_0$, does the Furstenberg–Zimmer structure theorem imply $\Pi^1_1\text{-}\mathsf{CA}_0$?...

L3
Logic
AMR-074-0120
Partially Solved

Well-Ordered Linearizations

v1.3 research notes

Over $\mathsf{RCA}_0$, is $\mathsf{EXT}(\omega^*)$ — the assertion that every well-founded partial order has a well-ordered linearization — equivalent...

L3
Logic
AMR-074-0121
Partially Solved

Reverse Mathematics of Fraïssé's Conjecture

v1.3 research notes

Over $\mathsf{RCA}_0$, is Fraïssé's conjecture for countable linear orders equivalent to $\mathsf{ATR}_0$?...

L3
Logic
AMR-074-0122
Open

Lengths of Bounded-Rank Linear-Order WQOs

v1.3 research notes

For an ordinal $\alpha$, determine the length (maximal order type) of the well-quasi-order $L_\alpha$ of countable linear orders of Hausdorff rank bel...

L3
Logic
AMR-074-0124
Open

Strengths of Laver and Nash–Williams BQO Theorems

v1.3 research notes

Determine the reverse-mathematical strengths of Laver's labeled-linear-order theorem $\mathsf{LAV}$ and the Nash–Williams bqo transfinite-sequence the...

L3
Logic
AMR-074-0125
Partially Solved

Three-Element Better-Quasi-Order

v1.3 research notes

Is there a subsystem weaker than $\mathsf{ATR}_0$ that proves that the three-element antichain is a better-quasi-order?...

L3
Logic
AMR-074-0131
Open

Weak Infinitary Comprehension versus Weak Choice

v1.3 research notes

Is weak-$L_{\omega_1,\omega}$-$\mathsf{CA}$ equivalent to weak-$\Sigma^1_1$-$\mathsf{AC}_0$?...

L3
Logic
AMR-074-0204
Open

Open Mapping Theorem for Separable Banach Spaces

v1.3 research notes

Is the open mapping theorem for separable Banach spaces provable in $\mathsf{RCA}_0$, or at least in $\mathsf{WKL}_0$?...

L3
Logic
AMR-074-0205
Open

Strength of the Krein–Šmulian Theorem

v1.3 research notes

Determine the exact reverse-mathematical strength of the Krein–Šmulian theorem for separable Banach spaces....

L3
Logic
AMR-074-0208
Open

Strength of Szemerédi's Theorem

v1.3 research notes

Is Szemerédi's theorem provable in $\mathsf{ACA}_0$? More generally, determine its reverse-mathematical strength....

L3
Logic
AMR-074-0216
Partially Solved

Ramsey's Theorem for Triples over a Weak Base

v1.3 research notes

Over $\mathsf{RCA}^*_0$, is Ramsey's theorem for triples equivalent to $\mathsf{ACA}_0$, as it is over $\mathsf{RCA}_0$?...

L3
Logic
AMR-077-0001
Partially Solved

Soft Phases in Two-Dimensional O(N) Models

v1.3 research notes

Do spin correlations in the classical Heisenberg model, and other $O(N)$ models with $N>2$, decay exponentially at every nonzero temperature, or do th...

L3
Mathematical Physics
AMR-077-0004
Partially Solved

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...

L3
Mathematical Physics
AMR-077-0005
Partially Solved

Extended States with Extensive Disorder

v1.3 research notes

Establish, in some energy range, the existence of extended eigenstates or continuous spectrum for linear operators with extensive disorder, such as a ...

L3
Mathematical Physics
AMR-077-0007
Partially Solved

One-Dimensional Fermi Gas with Attractive Interaction

v1.3 research notes

Determine the large-distance behavior of the one-particle reduced density matrix for a one-dimensional Fermi gas with spin and attractive interaction....

L3
Mathematical Physics
AMR-077-0008
Partially Solved

Entropy Production in Nonequilibrium Statistical Mechanics

v1.3 research notes

Give a fundamental and experimentally accessible definition of the entropy creation rate for general classical systems in stationary nonequilibrium st...

L3
Mathematical Physics
AMR-077-0012
Open

Optimal Flux for the Quarter-Filled Band

v1.3 research notes

For the two-dimensional square-lattice model of independent electrons at density $1/4$, does magnetic flux $\pi/2$ per plaquette minimize the ground-s...

L3
Mathematical Physics
AMR-077-0013
Open

Bose-Einstein Condensation in Continuum Models

v1.3 research notes

Prove that Bose-Einstein condensation occurs in a continuum model of a weakly interacting Bose gas, or determine whether the long-held assertion fails...

L3
Mathematical Physics
AMR-077-0014
Partially Solved

Meaning and Impossibility of Exact Helium Energy Levels

v1.3 research notes

Give a mathematically precise meaning to determining the energy levels of the helium atom exactly, in the sense that hydrogen energy levels are exact,...

L3
Mathematical Physics
AMR-078-0001
Open

Extended States in the Anderson Model

v1.3 research notes

Prove that the Anderson model has purely absolutely continuous spectrum in dimension $\nu\geq 3$, for suitable disorder width $b-a$, in some energy ra...

L3
Mathematical Physics
AMR-078-0002
Open

Localization in Two Dimensions

v1.3 research notes

Prove that the spectrum of the Anderson model in dimension $\nu=2$ is dense pure point....

L3
Mathematical Physics
AMR-078-0003
Open

Quantum Diffusion in the Anderson Model

v1.3 research notes

For the Anderson model in dimension $\nu\geq3$ and disorder strengths $|b-a|$ admitting absolutely continuous spectrum, prove that $\sum_{n\in\mathbb ...

L3
Mathematical Physics
AMR-078-0008
Partially Solved

Absolutely Continuous Spectrum Under a Weighted L2 Condition

v1.3 research notes

Let $V$ 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...

L3
Mathematical Physics
AMR-078-0009
Partially Solved

Bounded Excess Electrons

v1.3 research notes

For 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...

L3
Mathematical Physics
AMR-078-0010
Open

Asymptotics of Atomic Ionization Energy

v1.3 research notes

For 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...

L3
Mathematical Physics
AMR-078-0012
Partially Solved

First-Principles Molecular Configurations

v1.3 research notes

Give a mathematically rigorous justification of the techniques used to determine molecular configurations from first principles....

L3
Mathematical Physics
AMR-078-0014
Partially Solved

Continuity of the Integrated Density of States

v1.3 research notes

Prove that the integrated density of states $k(E)$ is continuous as a function of the energy $E$....

L3
Mathematical Physics
AMR-078-0015
Partially Solved

One-Dimensional Lieb-Thirring Constants

v1.3 research notes

For 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...

L3
Mathematical Physics
AMR-079-0003
Partially Solved

Riemann-Hilbert Problem with non-analytic data

v1.3 research notes

In many situations one is concerned with the asymptotic behavior of Riemann-Hilbert problems with exponentially varying data of the form $e^{in\phi(z)...

L3
Mathematical Physics
AMR-079-0004
Open

Painlev\'e equations

v1.3 research notes

What 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 ...

L3
Mathematical Physics
AMR-079-0005
Partially Solved

Multivariate analysis

v1.3 research notes

Random matrix theory was introduced into theoretical physics by Wigner in the 1950s in his study of neutron scattering resonances, but as a subject, R...

L3
Mathematical Physics
AMR-079-0007
Partially Solved

Non-self adjoint spectral problems

v1.3 research notes

Much is now known, theoretically and also numerically, about the spectrum of self-adjoint operators. This is in great contrast to the situation regard...

L3
Mathematical Physics
AMR-079-0008
Partially Solved

Long-time behavior with non-generic initial data

v1.3 research notes

The 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...

L3
Mathematical Physics
AMR-079-0009
Partially Solved

The parking problem

v1.3 research notes

A number of so-called ``transportation'' problems have now been analyzed in terms of RMT. These include: the ``vicious'' walker problem of M. Fisher, ...

L3
Mathematical Physics
AMR-079-0011
Partially Solved

The Toda lattice with random initial data

v1.3 research notes

Let $J$ be a random tridiagonal matrix drawn from the tridiagonal Gaussian orthogonal ensemble and evolve it by the finite nonperiodic Toda flow, so i...

L3
Mathematical Physics
AMR-079-0012
Partially Solved

Perturbation theory for infinite dimensional integrable systems

v1.3 research notes

The bijective mapping properties of the scattering transform for a variety of integrable systems on the line between appropriate weighted Sobolev spac...

L3
Mathematical Physics
AMR-079-0013
Solved

Perturbation theory for exactly solvable combinatorial problems

v1.3 research notes

The 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...

L3
Mathematical Physics
AMR-079-0014
Partially Solved

Initial/boundary value problems for integrable systems

v1.3 research notes

In the late 1990s Fokas introduced a new, more flexible approach to inverse scattering theory, and in recent years a number of researchers (Fokas, Its...

L3
Mathematical Physics
AMR-079-0015
Partially Solved

Multi-matrix models and models with an external field

v1.3 research notes

There has been considerable progress (Kuijlaars,...) in understanding basic statistics such as the correlation functions for the 2-matrix random matri...

L3
Mathematical Physics
AMR-080-0004
Partially Solved

numerical computation with random data

v1.3 research notes

Standard algorithms to compute the eigenvalues of a random matrix $H$ are completely integrable Hamiltonian systems (see ). The question raised in was...

L3
Mathematical Physics
AMR-081-0002
Open

Mutually Unbiased Bases in Dimension Six

v1.3 research notes

Construct a set of at least four mutually unbiased bases in dimension six, or prove that there are no seven mutually unbiased bases in $\mathcal{H}_6$...

L3
Mathematical Physics
AMR-083-0002
Open

O3 — Finding a prime above a bound

v1.3 research notes

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

L3
Graph Theory
AMR-083-0003
Open

O4 — Finding a prime in an arithmetic progression

v1.3 research notes

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

L3
Graph Theory
AMR-083-0004
Open

O5a — Deterministic polynomial-time integer factorization

v1.3 research notes

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

L3
Graph Theory
AMR-083-0005
Open

O5b — Randomized polynomial-time integer factorization

v1.3 research notes

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

L3
Graph Theory
AMR-083-0006
Open

O6 — Factoring a positive-density set of integers

v1.3 research notes

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...

L3
Graph Theory
AMR-083-0007
Open

O7a — Computing the squarefree part

v1.3 research notes

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

L3
Graph Theory
AMR-083-0008
Open

O7b — Factoring from a squarefree-part oracle

v1.3 research notes

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

L3
Graph Theory
AMR-083-0009
Partially Solved

O8 — Deterministic polynomial-time squarefreeness testing

v1.3 research notes

Can one decide in deterministic polynomial time whether an integer $n$ is squarefree?...

L3
Graph Theory
AMR-083-0010
Open

O9 — Counting distinct prime factors

v1.3 research notes

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

L3
Graph Theory