Unsolved Problems

Showing 251-300 of 548 problems (Page 6 of 11)

ALG-022
Open

Serre's Positivity Conjecture

If $R$ is a regular local ring and $P, Q$ are prime ideals with intersecting dimensions satisfying a certain condition, is the intersection multiplici...

L5
Algebra
156
13
NT-029
Open

Artin's Conjecture on Primitive Roots

For how many prime numbers $p$ is a given integer $a$ (not $\pm 1$ or a perfect square) a primitive root modulo $p$?...

L5
Number Theory
267
23
NT-030
Open

The abc Conjecture

For coprime integers $a, b, c$ with $a + b = c$, is $c$ usually not much larger than the product of distinct primes dividing $abc$?...

L5
Number Theory
892
76
GEO-010
Open

The Shephard's Problem

Can the unit ball in $\mathbb{R}^n$ be illuminated by fewer than $2^n$ directions?...

L4
Geometry
198
17
GEO-011
Solved

The Banach-Tarski Paradox Question

What is the minimum number of pieces needed to perform a Banach-Tarski decomposition of the ball?...

L5
Geometry
567
48
ALG-023
Open

The Andrews-Curtis Conjecture

Can every balanced presentation of the trivial group be transformed into a trivial presentation by a sequence of Nielsen transformations and conjugati...

L4
Algebra
412
28
ALG-024
Open

The Bounded Burnside Problem

For which positive integers $m$ and $n$ is the free Burnside group $B(m,n)$ finite? In particular, is $B(2, 5)$ finite?...

L5
Algebra
687
52
ALG-025
Open

The Guralnick-Thompson Conjecture

What are the composition factors of finite groups appearing in genus-0 systems?...

L4
Algebra
298
19
ALG-026
Open

The Herzog-Schönheim Conjecture

If a finite system of left cosets of subgroups of a group $G$ partitions $G$, must some two subgroups have the same index?...

L4
Algebra
321
22
ALG-027
Open

The Inverse Galois Problem

Is every finite group the Galois group of some Galois extension of $\mathbb{Q}$?...

L5
Algebra
892
67
ALG-028
Open

The Isomorphism Problem for Coxeter Groups

Is there an algorithm to determine whether two Coxeter groups given by presentations are isomorphic?...

L4
Algebra
367
25
ALG-029
Open

Infinitude of Leinster Groups

Are there infinitely many Leinster groups?...

L3
Algebra
245
18
ALG-030
Open

Existence of Generalized Moonshine

Does generalized moonshine exist for all elements of the Monster group?...

L5
Algebra
543
41
ALG-031
Open

Finiteness of Finitely Presented Periodic Groups

Is every finitely presented periodic group finite?...

L5
Algebra
456
33
ALG-032
Open

The Surjunctivity Conjecture

Is every group surjunctive?...

L4
Algebra
389
27
ALG-033
Open

The Sofic Groups Conjecture

Is every discrete countable group sofic?...

L5
Algebra
612
48
ALG-034
Open

Arthur's Conjectures

What is the structure of the discrete spectrum of automorphic forms on reductive groups?...

L5
Algebra
478
35
ALG-035
Open

Dade's Conjecture

Is there a relationship between the numbers of irreducible characters in blocks of a finite group and its local subgroups?...

L4
Algebra
312
21
ALG-036
Open

The Demazure Conjecture

Can representations of semisimple algebraic groups be characterized over the integers?...

L4
Algebra
289
18
ALG-037
Solved

The Kazhdan-Lusztig Conjectures

How do values of Kazhdan-Lusztig polynomials at $1$ relate to multiplicities of irreducible representations in Verma modules?...

L5
Algebra
523
39
ALG-038
Solved

The McKay Conjecture

For a finite group $G$ and prime $p$, is the number of irreducible characters of degree not divisible by $p$ equal to the corresponding number for the...

L5
Algebra
645
47
GEO-012
Open

The Spherical Bernstein Problem

What is the classification of complete minimal hypersurfaces in spheres of all dimensions?...

L4
Geometry
387
24
GEO-013
Open

The Carathéodory Conjecture

Does every convex, closed, twice-differentiable surface in $\mathbb{R}^3$ have at least two umbilical points?...

L4
Geometry
456
31
GEO-014
Open

The Cartan-Hadamard Conjecture

Does the isoperimetric inequality hold for Cartan-Hadamard manifolds?...

L4
Geometry
523
39
GEO-015
Open

Chern's Affine Conjecture

Does the Euler characteristic of a compact affine manifold vanish?...

L4
Geometry
398
27
GEO-016
Open

Chern's Conjecture for Hypersurfaces in Spheres

What minimal hypersurfaces in spheres have constant mean curvature?...

L4
Geometry
367
23
GEO-017
Open

The Closed Curve Problem

What are necessary and sufficient conditions for an integral curve defined by two periodic functions to be closed?...

L3
Geometry
289
19
GEO-018
Open

The Filling Area Conjecture

Does a hemisphere have minimum area among shortcut-free surfaces with a given boundary length?...

L4
Geometry
334
22
GEO-019
Open

The Hopf Conjectures

What is the relationship between curvature and Euler characteristic for even-dimensional Riemannian manifolds?...

L5
Geometry
567
43
GEO-020
Open

The Osserman Conjecture

Is every Osserman manifold either flat or locally isometric to a rank-one symmetric space?...

L4
Geometry
412
28
GEO-021
Open

Yau's Conjecture on First Eigenvalues

Is the first eigenvalue of the Laplace-Beltrami operator on a minimal hypersurface in $S^{n+1}$ equal to $n$?...

L4
Geometry
478
34
GEO-022
Open

The Hadwiger Covering Conjecture

Can every $n$-dimensional convex body be covered by at most $2^n$ smaller homothetic copies?...

L4
Geometry
523
38
GEO-023
Open

The Happy Ending Problem

What is the minimum number of points in the plane needed to guarantee a convex $n$-gon?...

L4
Geometry
612
47
GEO-024
Open

The Heilbronn Triangle Problem

What is the largest minimum area of a triangle determined by $n$ points in a unit square?...

L4
Geometry
445
31
GEO-025
Open

Kalai's $3^d$ Conjecture

Does every centrally symmetric $d$-dimensional polytope have at least $3^d$ faces?...

L4
Geometry
378
26
GEO-026
Open

The Unit Distance Problem

What is the maximum number of unit distances determined by $n$ points in the plane?...

L4
Geometry
567
42
GEO-028
Open

Ehrhart's Volume Conjecture

Does a convex body in $\mathbb{R}^n$ with one interior lattice point at its center of mass have volume at most $(n+1)^n/n!$?...

L4
Geometry
389
27
ALG-039
Open

The Cherlin-Zilber Conjecture

Is every simple group with a stable first-order theory an algebraic group over an algebraically closed field?...

L5
Algebra
412
29
ALG-040
Open

The Generalized Star Height Problem

Can all regular languages be expressed with generalized regular expressions of bounded star height?...

L4
Algebra
334
23
NT-031
Open

Hilbert's Tenth Problem for Number Fields

For which number fields is there an algorithm to determine solvability of Diophantine equations?...

L5
Number Theory
523
39
ANA-006
Open

The Ibragimov-Iosifescu Conjecture

Does the central limit theorem hold for all φ-mixing sequences?...

L4
Analysis
378
26
GEO-029
Open

Borsuk's Conjecture

Can every bounded set in $\mathbb{R}^n$ be partitioned into $n+1$ sets of smaller diameter?...

L4
Geometry
523
39
GEO-030
Open

The Kissing Number Problem

What is the maximum number of non-overlapping unit spheres that can touch a central unit sphere in $n$ dimensions?...

L4
Geometry
612
46
GEO-031
Open

Ulam's Packing Conjecture

Is the sphere the worst-packing convex solid?...

L4
Geometry
445
32
GEO-032
Open

Sphere Packing in High Dimensions

What is the densest packing of unit spheres in dimensions other than 1, 2, 3, 8, and 24?...

L5
Geometry
734
58
ANA-008
Open

Lehmer's Conjecture

Is there a constant $c > 1$ such that all non-cyclotomic polynomials have Mahler measure at least $c$?...

L4
Analysis
489
36
ANA-009
Open

Fuglede's Conjecture

Is a measurable set in $\mathbb{R}^d$ spectral if and only if it tiles by translation?...

L4
Analysis
456
33
COMB-010
Open

The Cap Set Problem

What is the maximum size of a cap set in $\mathbb{F}_3^n$?...

L4
Combinatorics
523
40
COMB-012
Open

The Sunflower Conjecture

Does every family of at least $c^k k!$ sets of size $k$ contain a sunflower of size 3, for some absolute constant $c$?...

L5
Combinatorics
612
48
COMB-013
Open

Ramsey Number $R(5,5)$

What is the exact value of the Ramsey number $R(5,5)$?...

L4
Combinatorics
823
67