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How To Solve Word Problems In Mathematics David Wayne Pdf

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Many mathematical problems have not been solved yet. These unsolved problems occur in multiple domains, including theoretical physics, computer science, algebra, analysis, combinatorics, algebraic, differential, discrete and Euclidean geometries, graph, group, model, number, set and Ramsey theories, dynamical systems, and partial differential equations. Some problems may belong to more than one discipline of mathematics and be studied using techniques from different areas. Prizes are often awarded for the solution to a long-standing problem, and lists of unsolved problems, such as the list of Millennium Prize Problems, receive considerable attention.

This article is a composite of notable unsolved problems derived from many sources, including but not limited to lists considered authoritative. The list is not comprehensive, for at least the reason that entries may not be updated at the time of viewing. This list includes problems which are considered by the mathematical community to be widely varying in both difficulty and centrality to the science as a whole.

Lists of unsolved problems in mathematics [edit]

Various mathematicians and organizations have published and promoted lists of unsolved mathematical problems. In some cases, the lists have been associated with prizes for the discoverers of solutions.

List Number of
problems
Number unresolved
or incompletely resolved
Proposed by Proposed
in
Hilbert's problems[1] 23 15 David Hilbert 1900
Landau's problems[2] 4 4 Edmund Landau 1912
Taniyama's problems[3] 36 - Yutaka Taniyama 1955
Thurston's 24 questions[4] [5] 24 - William Thurston 1982
Smale's problems 18 14 Stephen Smale 1998
Millennium Prize problems 7 6[6] Clay Mathematics Institute 2000
Simon problems 15 <12[7] [8] Barry Simon 2000
Unsolved Problems on Mathematics for the 21st Century[9] 22 - Jair Minoro Abe, Shotaro Tanaka 2001
DARPA's math challenges[10] [11] 23 - DARPA 2007

Millennium Prize Problems [edit]

Of the original seven Millennium Prize Problems set by the Clay Mathematics Institute in 2000, six have yet to be solved as of August, 2021:[6]

  • Birch and Swinnerton-Dyer conjecture
  • Hodge conjecture
  • Navier–Stokes existence and smoothness
  • P versus NP
  • Riemann hypothesis
  • Yang–Mills existence and mass gap

The seventh problem, the Poincaré conjecture, has been solved;[12] however, a generalization called the smooth four-dimensional Poincaré conjecture—that is, whether a four-dimensional topological sphere can have two or more inequivalent smooth structures—is still unsolved.[13]

Unsolved problems [edit]

Algebra [edit]

Notebook problems [edit]

  • The Dneister Notebook (Dnestrovskaya Tetrad) collects several hundred unresolved problems in algebra, particularly ring theory and modulus theory.[14]
  • The Erlagol Notebook (Erlagolskaya Tetrad) collects unresolved problems in algebra and model theory.[15]

Conjectures and problems [edit]

  • Birch–Tate conjecture
  • Bombieri–Lang conjecture
  • Crouzeix's conjecture
  • Demazure conjecture
  • Eilenberg–Ganea conjecture
  • Farrell–Jones conjecture
  • Bost conjecture
  • Finite lattice representation problem[16]
  • Green's conjecture
  • Grothendieck–Katz p-curvature conjecture
  • Hadamard conjecture
  • Hadamard's maximal determinant problem
  • Hilbert's fifteenth problem
  • Hilbert's sixteenth problem
  • Homological conjectures in commutative algebra
  • Jacobson's conjecture
  • Kaplansky's conjectures
  • Köthe conjecture
  • Kummer–Vandiver conjecture
  • Existence of perfect cuboids and associated cuboid conjectures
  • Pierce–Birkhoff conjecture
  • Rota's basis conjecture
  • Sendov's conjecture
  • Serre's conjecture II
  • Serre's multiplicity conjectures
  • Uniform boundedness conjecture for rational points
  • Wild problem: Classification of pairs of n×n matrices under simultaneous conjugation and problems containing it such as a lot of classification problems
  • Zariski–Lipman conjecture
  • Zauner's conjecture: existence of SIC-POVMs in all dimensions

Analysis [edit]

Conjectures and problems [edit]

Open questions [edit]

  • Are γ {\displaystyle \gamma } (the Euler–Mascheroni constant), π +e, π −e, π e, π/e, π e , π 2 , π π , e π 2 , lnπ, 2 e , e e , Catalan's constant, or Khinchin's constant; rational, algebraic irrational, or transcendental? What is the irrationality measure of each of these numbers?[21] [22] [23]
  • What is the exact value of Landau's constants, including Bloch's constant?

Other [edit]

  • Regularity of solutions of Euler equations
  • Convergence of Flint Hills series
  • Regularity of solutions of Vlasov–Maxwell equations

Combinatorics [edit]

Conjectures and problems [edit]

Other [edit]

Dynamical systems [edit]

Conjectures and problems [edit]

  • Arnold–Givental conjecture and Arnold conjecture – relating symplectic geometry to Morse theory
  • Quantum chaos: Berry–Tabor conjecture
  • Birkhoff conjecture: if a billiard table is strictly convex and integrable, is its boundary necessarily an ellipse?[30]
  • Collatz conjecture (3n + 1 conjecture)
  • Eremenko's conjecture that every component of the escaping set of an entire transcendental function is unbounded
  • Furstenberg conjecture – Is every invariant and ergodic measure for the × 2 , × 3 {\displaystyle \times 2,\times 3} action on the circle either Lebesgue or atomic?
  • Kaplan–Yorke conjecture
  • Margulis conjecture – Measure classification for diagonalizable actions in higher-rank groups
  • MLC conjecture – Is the Mandelbrot set locally connected?
  • Many problems concerning an outer billiard, for example showing that outer billiards relative to almost every convex polygon have unbounded orbits.
  • Quantum unique ergodicity conjecture[31]
  • Weinstein conjecture – Does a regular compact contact type level set of a Hamiltonian on a symplectic manifold carry at least one periodic orbit of the Hamiltonian flow?

Open questions [edit]

  • Does every positive integer generate a juggler sequence terminating at 1?
  • Lyapunov function: Lyapunov's second method for stability – For what classes of ODEs, describing dynamical systems, does the Lyapunov's second method formulated in the classical and canonically generalized forms define the necessary and sufficient conditions for the (asymptotical) stability of motion?
  • Is every reversible cellular automaton in three or more dimensions locally reversible?[32]

Games and puzzles [edit]

Combinatorial games [edit]

  • Is there a non-terminating game of beggar-my-neighbour?
  • Sudoku:
    • How many puzzles have exactly one solution?[33]
      • How many puzzles with exactly one solution are minimal?[33]
    • What is the maximum number of givens for a minimal puzzle?[33]
  • Tic-tac-toe variants:
    • Given a width of tic-tac-toe board, what is the smallest dimension such that X is guaranteed a winning strategy?[34]
  • What is the Turing completeness status of all unique elementary cellular automata?

Games with imperfect information [edit]

  • Rendezvous problem

Geometry [edit]

Algebraic geometry [edit]

Conjectures [edit]
  • Abundance conjecture
  • Bass conjecture
  • Deligne conjecture
  • Dixmier conjecture
  • Fröberg conjecture
  • Fujita conjecture
  • Hartshorne's conjectures[35]
  • The Jacobian conjecture
  • Manin conjecture
  • Maulik–Nekrasov–Okounkov–Pandharipande conjecture on an equivalence between Gromov–Witten theory and Donaldson–Thomas theory[36]
  • Nakai conjecture
  • Parshin's conjecture
  • Section conjecture
  • Standard conjectures on algebraic cycles
  • Tate conjecture
  • Virasoro conjecture
  • Weight-monodromy conjecture
  • Zariski multiplicity conjecture[37]
Other [edit]
  • Flip - Termination of flips
  • Resolution of singularities in characteristic p {\displaystyle p}

Covering and packing [edit]

Conjectures and problems [edit]
  • Borsuk's problem on upper and lower bounds for the number of smaller-diameter subsets needed to cover a bounded n-dimensional set.
  • The covering problem of Rado: if the union of finitely many axis-parallel squares has unit area, how small can the largest area covered by a disjoint subset of squares be?[38]
  • The Erdős–Oler conjecture that when n {\displaystyle n} is a triangular number, packing n 1 {\displaystyle n-1} circles in an equilateral triangle requires a triangle of the same size as packing n {\displaystyle n} circles[39]
  • The kissing number problem for dimensions other than 1, 2, 3, 4, 8 and 24[40]
  • Reinhardt's conjecture that the smoothed octagon has the lowest maximum packing density of all centrally-symmetric convex plane sets[41]
  • Sphere packing problems, including the density of the densest packing in dimensions other than 1, 2, 3, 8 and 24, and its asymptotic behavior for high dimensions.
  • Square packing in a square: what is the asymptotic growth rate of wasted space?[42]
  • Ulam's packing conjecture about the identity of the worst-packing convex solid[43]

Differential geometry [edit]

Conjectures and problems [edit]
  • The spherical Bernstein's problem, a possible generalization of the original Bernstein's problem
  • Carathéodory conjecture
  • Cartan–Hadamard conjecture: Can the classical isoperimetric inequality for subsets of Euclidean space be extended to spaces of nonpositive curvature, known as Cartan–Hadamard manifolds?
  • Chern's conjecture (affine geometry)
  • Chern's conjecture for hypersurfaces in spheres
  • Closed curve problem: Find (explicit) necessary and sufficient conditions that determine when, given two periodic functions with the same period, the integral curve is closed.[44]
  • The filling area conjecture, that a hemisphere has the minimum area among shortcut-free surfaces in Euclidean space whose boundary forms a closed curve of given length[45]
  • The Hopf conjectures relating the curvature and Euler characteristic of higher-dimensional Riemannian manifolds[46]
  • Yau's conjecture
  • Yau's conjecture on the first eigenvalue

Discrete geometry [edit]

In three dimensions, the kissing number is 12, because 12 non-overlapping unit spheres can be put into contact with a central unit sphere. (Here, the centers of outer spheres form the vertices of a regular icosahedron.) Kissing numbers are only known exactly in dimensions 1, 2, 3, 4, 8 and 24.

Conjectures and problems [edit]
Open questions [edit]
  • How many unit distances can be determined by a set of n points in the Euclidean plane?[53]
Other [edit]
  • Finding matching upper and lower bounds for k-sets and halving lines[54]
  • Tripod packing[55]

Euclidean geometry [edit]

Conjectures and problems [edit]
Open questions [edit]
  • Borromean rings — are there three unknotted space curves, not all three circles, which cannot be arranged to form this link?[71]
  • Dissection into orthoschemes – is it possible for simplices of every dimension?[72]
Other [edit]
  • Uniform 5-polytopes – find and classify the complete set of these shapes[73]

Graph theory [edit]

Graph coloring and labeling [edit]

An instance of the Erdős–Faber–Lovász conjecture: a graph formed from four cliques of four vertices each, any two of which intersect in a single vertex, can be four-colored.

Conjectures and problems [edit]
  • Cereceda's conjecture on the diameter of the space of colorings of degenerate graphs[74]
  • The Erdős–Faber–Lovász conjecture on coloring unions of cliques[75]
  • The Gyárfás–Sumner conjecture on χ-boundedness of graphs with a forbidden induced tree[76]
  • The Hadwiger conjecture relating coloring to clique minors[77]
  • The Hadwiger–Nelson problem on the chromatic number of unit distance graphs[78]
  • Jaeger's Petersen-coloring conjecture that every bridgeless cubic graph has a cycle-continuous mapping to the Petersen graph[79]
  • The list coloring conjecture that, for every graph, the list chromatic index equals the chromatic index[80]
  • The total coloring conjecture of Behzad and Vizing that the total chromatic number is at most two plus the maximum degree[81]

Graph drawing [edit]

Conjectures and problems [edit]
  • The Albertson conjecture that the crossing number can be lower-bounded by the crossing number of a complete graph with the same chromatic number[82]
  • The Blankenship–Oporowski conjecture on the book thickness of subdivisions[83]
  • Conway's thrackle conjecture[84]
  • Harborth's conjecture that every planar graph can be drawn with integer edge lengths[85]
  • Negami's conjecture on projective-plane embeddings of graphs with planar covers[86]
  • The strong Papadimitriou–Ratajczak conjecture that every polyhedral graph has a convex greedy embedding[87]
  • Turán's brick factory problem – Is there a drawing of any complete bipartite graph with fewer crossings than the number given by Zarankiewicz?[88]
Other [edit]
  • Universal point sets of subquadratic size for planar graphs[89]

Paths and cycles in graphs [edit]

Conjectures and problems [edit]
  • Barnette's conjecture that every cubic bipartite three-connected planar graph has a Hamiltonian cycle[90]
  • Chvátal's toughness conjecture, that there is a number t such that every t-tough graph is Hamiltonian[91]
  • The cycle double cover conjecture that every bridgeless graph has a family of cycles that includes each edge twice[92]
  • The Erdős–Gyárfás conjecture on cycles with power-of-two lengths in cubic graphs[93]
  • The linear arboricity conjecture on decomposing graphs into disjoint unions of paths according to their maximum degree[94]
  • The Lovász conjecture on Hamiltonian paths in symmetric graphs[95]
  • The Oberwolfach problem on which 2-regular graphs have the property that a complete graph on the same number of vertices can be decomposed into edge-disjoint copies of the given graph.[96]
  • Szymanski's conjecture

Word-representation of graphs [edit]

  • Are there any graphs on n vertices whose representation requires more than floor(n/2) copies of each letter?[97] [98] [99] [100]
  • Characterise (non-)word-representable planar graphs[97] [98] [99] [100]
  • Characterise word-representable graphs in terms of (induced) forbidden subgraphs.[97] [98] [99] [100]
  • Characterise word-representable near-triangulations containing the complete graph K 4 (such a characterisation is known for K 4-free planar graphs[101])
  • Classify graphs with representation number 3, that is, graphs that can be represented using 3 copies of each letter, but cannot be represented using 2 copies of each letter[102]
  • Is it true that out of all bipartite graphs, crown graphs require longest word-representants?[103]
  • Is the line graph of a non-word-representable graph always non-word-representable?[97] [98] [99] [100]
  • Which (hard) problems on graphs can be translated to words representing them and solved on words (efficiently)?[97] [98] [99] [100]

Miscellaneous graph theory [edit]

Conjectures and problems [edit]
Open questions [edit]
  • Does a Moore graph with girth 5 and degree 57 exist?[118]
  • What is the largest possible pathwidth of an n-vertex cubic graph?[119]

Group theory [edit]

The free Burnside group B ( 2 , 3 ) {\displaystyle B(2,3)} is finite; in its Cayley graph, shown here, each of its 27 elements is represented by a vertex. The question of which other groups B ( m , n ) {\displaystyle B(m,n)} are finite remains open.

Notebook problems [edit]

  • The Kourovka Notebook is a collection of unsolved problems in group theory, first published in 1965 and updated many times since.[120]

Conjectures and problems [edit]

  • Andrews–Curtis conjecture
  • Guralnick–Thompson conjecture[121]
  • Herzog–Schönheim conjecture
  • The inverse Galois problem: is every finite group the Galois group of a Galois extension of the rationals?
  • Problems in loop theory and quasigroup theory consider generalizations of groups

Open questions [edit]

  • Are there an infinite number of Leinster groups?
  • Does generalized moonshine exist?
  • For which positive integers m, n is the free Burnside group B(m,n) finite? In particular, is B(2, 5) finite?
  • Is every finitely presented periodic group finite?
  • Is every group surjunctive?

Model theory and formal languages [edit]

Conjectures and problems [edit]

Open questions [edit]

Other [edit]

  • Determine the structure of Keisler's order[133] [134]

Number theory [edit]

General [edit]

6 is a perfect number because it is the sum of its proper positive divisors, 1, 2 and 3. It is not known how many perfect numbers there are, nor if any of them are odd.

Conjectures, problems and hypotheses [edit]
  • André–Oort conjecture
  • Beilinson conjecture
  • Brocard's problem: existence of integers, (n,m), such that n! + 1 =m 2 other than n = 4, 5, 7
  • Carmichael's totient function conjecture
  • Casas-Alvero conjecture
  • Catalan–Dickson conjecture on aliquot sequences
  • Congruent number problem (a corollary to Birch and Swinnerton-Dyer conjecture, per Tunnell's theorem)
  • Erdős–Moser problem: is 11 + 21 = 31 the only solution to the Erdős–Moser equation?
  • Erdős–Straus conjecture
  • Erdős–Ulam problem
  • Exponent pair conjecture (Van der Corput's method)
  • The Gauss circle problem – how far can the number of integer points in a circle centered at the origin be from the area of the circle?
  • Goormaghtigh conjecture
  • Grand Riemann hypothesis
    • Generalized Riemann hypothesis
      • Riemann hypothesis
  • Grimm's conjecture
  • Hall's conjecture
  • Hardy–Littlewood zeta-function conjectures
  • Hilbert's eleventh problem
  • Hilbert's ninth problem
  • Hilbert's twelfth problem
  • Hilbert–Pólya conjecture
  • Keating–Snaith conjecture concerning the asymptotics of an integral involving the Riemann zeta function[135]
  • Lehmer's totient problem: if φ(n) divides n − 1, must n be prime?
  • Leopoldt's conjecture
  • Lindelöf hypothesis and its consequence, the density hypothesis for zeroes of the Riemann zeta function (see Bombieri–Vinogradov theorem)
  • Littlewood conjecture
  • Mahler's 3/2 problem
  • Montgomery's pair correlation conjecture
  • n conjecture
    • abc conjecture
    • Szpiro's conjecture
  • Newman's conjecture
  • Pillai's conjecture
  • Piltz divisor problem, especially Dirichlet's divisor problem
  • Ramanujan–Petersson conjecture
  • Sato–Tate conjecture
  • Scholz conjecture
  • Do Siegel zeros exist?
  • Singmaster's conjecture: is there a finite upper bound on the multiplicities of the entries greater than 1 in Pascal's triangle?[136]
  • The uniqueness conjecture for Markov numbers[137]
  • Vojta's conjecture
Open questions [edit]
  • Are there 65, 66, or 67 idoneal numbers?
  • Are there any pairs of amicable numbers which have opposite parity?
  • Are there any pairs of betrothed numbers which have same parity?
  • Are there any pairs of relatively prime amicable numbers?
  • Are there infinitely many amicable numbers?
  • Are there infinitely many betrothed numbers?
  • Are there infinitely many Giuga numbers?
  • Are there infinitely many perfect numbers?
  • Does every rational number with an odd denominator have an odd greedy expansion?
  • Do any Lychrel numbers exist?
  • Do any odd perfect numbers exist?
  • Do any odd noncototients exist?
  • Do any odd superperfect numbers exist?
  • Do any odd weird numbers exist?
  • Do any Taxicab(5, 2, n) exist for n > 1?
  • Do quasiperfect numbers exist?
  • Is there a covering system with odd distinct moduli?[138]
  • Is π a normal number (its digits are "random")?[139]
  • Is 10 a solitary number?
  • Which integers can be written as the sum of three perfect cubes?[140]
Other [edit]
  • Find the value of the De Bruijn–Newman constant

Additive number theory [edit]

Conjectures and problems [edit]
  • Beal's conjecture
  • Erdős conjecture on arithmetic progressions
  • Erdős–Turán conjecture on additive bases
  • Fermat–Catalan conjecture
  • Gilbreath's conjecture
  • Goldbach's conjecture
  • Lander, Parkin, and Selfridge conjecture
  • Lemoine's conjecture
  • Minimum overlap problem
  • Pollock's conjectures
  • Skolem problem
  • The values of g(k) and G(k) in Waring's problem
Open questions [edit]
  • Do the Ulam numbers have a positive density?
Other [edit]
  • Determine growth rate of r k (N) (see Szemerédi's theorem)

Algebraic number theory [edit]

Conjectures and problems [edit]
  • Class number problem: are there infinitely many real quadratic number fields with unique factorization?
  • Fontaine–Mazur conjecture
  • Gan–Gross–Prasad conjecture
  • Greenberg's conjectures
  • Hermite's problem
  • Kummer–Vandiver conjecture
  • Lang and Trotter's conjecture on supersingular primes
  • Selberg's 1/4 conjecture
  • Stark conjectures (including Brumer–Stark conjecture)
Other [edit]
  • Characterize all algebraic number fields that have some power basis.

Computational number theory [edit]

  • Integer factorization: Can integer factorization be done in polynomial time?

Prime numbers [edit]

Goldbach's conjecture states that all even integers greater than 2 can be written as the sum of two primes. Here this is illustrated for the even integers from 4 to 28.

Conjectures, problems and hypotheses [edit]
  • Agoh–Giuga conjecture
  • Artin's conjecture on primitive roots
  • Brocard's conjecture
  • Bunyakovsky conjecture
  • Catalan's Mersenne conjecture
  • Dickson's conjecture
  • Dubner's conjecture
  • Elliott–Halberstam conjecture
  • Erdős–Mollin–Walsh conjecture
  • Feit–Thompson conjecture
  • Fortune's conjecture (that no Fortunate number is composite)
  • The Gaussian moat problem: is it possible to find an infinite sequence of distinct Gaussian prime numbers such that the difference between consecutive numbers in the sequence is bounded?
  • Gillies' conjecture
  • Goldbach conjecture
  • Landau's problems
  • Problems associated to Linnik's theorem
  • New Mersenne conjecture
  • Polignac's conjecture
  • Schinzel's hypothesis H
  • Is 78,557 the lowest Sierpiński number (so-called Selfridge's conjecture)?
  • Twin prime conjecture
  • Does the conjectural converse of Wolstenholme's theorem hold for all natural numbers?
Open questions [edit]
  • Are all Euclid numbers square-free?
  • Are all Fermat numbers square-free?
  • Are all Mersenne numbers of prime index square-free?
  • Are there any composite c satisfying 2 c − 1 ≡ 1 (mod c 2)?
  • Are there any Wall–Sun–Sun primes?
  • Are there any Wieferich primes in base 47?
  • Are there infinitely many balanced primes?
  • Are there infinitely many Carol primes?
  • Are there infinitely many cousin primes?
  • Are there infinitely many Cullen primes?
  • Are there infinitely many Euclid primes?
  • Are there infinitely many Fibonacci primes?
  • Are there infinitely many Kummer primes?
  • Are there infinitely many Kynea primes?
  • Are there infinitely many Lucas primes?
  • Are there infinitely many Mersenne primes (Lenstra–Pomerance–Wagstaff conjecture); equivalently, infinitely many even perfect numbers?
  • Are there infinitely many Newman–Shanks–Williams primes?
  • Are there infinitely many palindromic primes to every base?
  • Are there infinitely many Pell primes?
  • Are there infinitely many Pierpont primes?
  • Are there infinitely many prime quadruplets?
  • Are there infinitely many prime triplets?
  • Are there infinitely many regular primes, and if so is their relative density e 1 / 2 {\displaystyle e^{-1/2}} ?
  • Are there infinitely many sexy primes?
  • Are there infinitely many safe and Sophie Germain primes?
  • Are there infinitely many Wagstaff primes?
  • Are there infinitely many Wieferich primes?
  • Are there infinitely many Wilson primes?
  • Are there infinitely many Wolstenholme primes?
  • Are there infinitely many Woodall primes?
  • Can a prime p satisfy 2 p − 1 ≡ 1 (mod p 2) and 3 p − 1 ≡ 1 (modp 2) simultaneously?[141]
  • Does every prime number appear in the Euclid–Mullin sequence?
  • Find the smallest Skewes' number
  • For any given integer a > 0, are there infinitely many Lucas–Wieferich primes associated with the pair (a, −1)? (Specially, when a = 1, this is the Fibonacci-Wieferich primes, and when a = 2, this is the Pell-Wieferich primes)
  • For any given integer a > 0, are there infinitely many primes p such that a p − 1 ≡ 1 (mod p 2)?[142]
  • For any given integer a which is not a square and does not equal to −1, are there infinitely many primes with a as a primitive root?
  • For any given integer b which is not a perfect power and not of the form −4k 4 for integer k, are there infinitely many repunit primes to base b?
  • For any given integers k ≥ 1, b ≥ 2, c ≠ 0, with gcd(k, c) = 1 and gcd(b, c) = 1, are there infinitely many primes of the form (k×b n +c)/gcd(k+c,b−1) with integer n ≥ 1?
  • Is every Fermat number 22 n  + 1 composite for n > 4 {\displaystyle n>4} ?
  • Is 509,203 the lowest Riesel number?

Set theory [edit]

Note: These conjectures are about models of Zermelo-Frankel set theory with choice, and may not be able to be expressed in models of other set theories such as the various constructive set theories or non-wellfounded set theory.

Conjectures, problems, and hypotheses [edit]

Open questions [edit]

  • Does the consistency of the existence of a strongly compact cardinal imply the consistent existence of a supercompact cardinal?
  • Does there exist a Jónsson algebra on ℵω?
  • Is OCA (Open coloring axiom) consistent with 2 0 > 2 {\displaystyle 2^{\aleph _{0}}>\aleph _{2}} ?
  • Without assuming the axiom of choice, can a nontrivial elementary embedding VV exist?

Topology [edit]

Conjectures and problems [edit]

  • Baum–Connes conjecture
  • Bing–Borsuk conjecture
  • Borel conjecture
  • Halperin conjecture
  • Hilbert–Smith conjecture
  • Mazur's conjectures[143]
  • Novikov conjecture
  • Telescope conjectures
  • Unknotting problem
  • Volume conjecture
  • Whitehead conjecture
  • Zeeman conjecture

Problems solved since 1995 [edit]

Algebra [edit]

  • Connes embedding problem (Zhengfeng Ji, Anand Natarajan, Thomas Vidick, John Wright, Henry Yuen, 2020)

Analysis [edit]

Combinatorics [edit]

  • Erdős sumset conjecture (Joel Moreira, Florian Richter, Donald Robertson, 2018)[146]
  • McMullen's g-conjecture on the possible numbers of faces of different dimensions in a simplicial sphere (also Grünbaum conjecture, several conjectures of Kühnel) (Karim Adiprasito, 2018)[147] [148]
  • Hirsch conjecture (Francisco Santos Leal, 2010)[149] [150]

Dynamical systems [edit]

  • Painlevé conjecture (Jinxin Xue, 2014)[151] [152]

Game theory [edit]

  • The angel problem (Various independent proofs, 2006)[153] [154] [155] [156]

Geometry [edit]

21st century [edit]

  • Yau's conjecture (Antoine Song, 2018)[157] [158]
  • Pentagonal tiling (Michaël Rao, 2017)[159]
  • Erdős distinct distances problem (Larry Guth, Netz Hawk Katz, 2011)[160]
  • Heterogeneous tiling conjecture (squaring the plane) (Frederick V. Henle and James M. Henle, 2008)[161]

20th century [edit]

  • Kepler conjecture (Ferguson, Hales, 1998)[162]
  • Dodecahedral conjecture (Hales, McLaughlin, 1998)[163]

Graph theory [edit]

  • Ringel's conjecture on graceful labeling of trees (Richard Montgomery, Benny Sudakov, Alexey Pokrovskiy, 2020)[164] [165]
  • Hedetniemi's conjecture on the chromatic number of tensor products of graphs (Yaroslav Shitov, 2019)[166]
  • Babai's problem (Problem 3.3 in "Spectra of Cayley graphs") (Alireza Abdollahi, Maysam Zallaghi, 2015)[167]
  • Alspach's conjecture (Darryn Bryant, Daniel Horsley, William Pettersson, 2014)
  • Scheinerman's conjecture (Jeremie Chalopin and Daniel Gonçalves, 2009)[168]
  • Erdős–Menger conjecture (Aharoni, Berger 2007)[169]
  • Road coloring conjecture (Avraham Trahtman, 2007)[170]

Group theory [edit]

  • Hanna Neumann conjecture (Mineyev, 2011)[171]
  • Density theorem (Namazi, Souto, 2010)[172]
  • Full classification of finite simple groups (Harada, Solomon, 2008)

Number theory [edit]

21st century [edit]

  • Duffin-Schaeffer conjecture (Dimitris Koukoulopoulos, James Maynard, 2019)
  • Main conjecture in Vinogradov's mean-value theorem (Jean Bourgain, Ciprian Demeter, Larry Guth, 2015)[173]
  • Goldbach's weak conjecture (Harald Helfgott, 2013)[174] [175] [176]
  • Serre's modularity conjecture (Chandrashekhar Khare and Jean-Pierre Wintenberger, 2008)[177] [178] [179]
  • Existence of bounded gaps between primes (Yitang Zhang, Polymath8, James Maynard, 2013)[180] [181] [182]

20th century [edit]

  • Fermat's Last Theorem (Andrew Wiles and Richard Taylor, 1995)[183] [184]

Ramsey theory [edit]

  • Burr–Erdős conjecture (Choongbum Lee, 2017)[185]
  • Boolean Pythagorean triples problem (Marijn Heule, Oliver Kullmann, Victor Marek, 2016)[186] [187]

Theoretical computer science [edit]

  • Sensitivity conjecture for Boolean functions (Hao Huang, 2019) [188]

Topology [edit]

  • Deciding whether the Conway knot is a slice knot (Lisa Piccirillo, 2020)[189] [190]
  • Virtual Haken conjecture (Agol, Groves, Manning, 2012)[191] (and by work of Wise also virtually fibered conjecture)
  • Hsiang–Lawson's conjecture (Brendle, 2012)[192]
  • Ehrenpreis conjecture (Kahn, Markovic, 2011)[193]
  • Atiyah conjecture (Austin, 2009)[194]
  • Cobordism hypothesis (Jacob Lurie, 2008)[195]
  • Geometrization conjecture, proven by Grigori Perelman[196] in a series of preprints in 2002–2003.[197]
  • Spherical space form conjecture (Grigori Perelman, 2006)

Uncategorised [edit]

21st century [edit]

2010s [edit]
  • Erdős discrepancy problem (Terence Tao, 2015)[198]
  • Umbral moonshine conjecture (John F. R. Duncan, Michael J. Griffin, Ken Ono, 2015)[199]
  • Anderson conjecture (Cheeger, Naber, 2014)[200]
  • Gaussian correlation inequality (Thomas Royen, 2014)[201]
  • Willmore conjecture (Fernando Codá Marques and André Neves, 2012)[202]
  • Beck's 3-permutations conjecture (Newman, Nikolov, 2011)[203]
  • Bloch–Kato conjecture (Voevodsky, 2011)[204] (and Quillen–Lichtenbaum conjecture and by work of Geisser and Levine (2001) also Beilinson–Lichtenbaum conjecture[205] [206] [207])
  • Sidon set problem (J. Cilleruelo, I. Ruzsa and C. Vinuesa, 2010)[208]
2000s [edit]
  • Kauffman–Harary conjecture (Matmann, Solis, 2009)[209]
  • Surface subgroup conjecture (Kahn, Markovic, 2009)[210]
  • Normal scalar curvature conjecture and the Böttcher–Wenzel conjecture (Lu, 2007)[211]
  • Nirenberg–Treves conjecture (Nils Dencker, 2005)[212] [213]
  • Lax conjecture (Lewis, Parrilo, Ramana, 2005)[214]
  • The Langlands–Shelstad fundamental lemma (Ngô Bảo Châu and Gérard Laumon, 2004)[215]
  • Tameness conjecture and Ahlfors measure conjecture (Ian Agol, 2004)[216]
  • Robertson–Seymour theorem (Robertson, Seymour, 2004)[217]
  • Stanley–Wilf conjecture (Gábor Tardos and Adam Marcus, 2004)[218] (and also Alon–Friedgut conjecture)
  • Green–Tao theorem (Ben J. Green and Terence Tao, 2004)[219]
  • Ending lamination theorem (Jeffrey F. Brock, Richard D. Canary, Yair N. Minsky, 2004)[220]
  • Carpenter's rule problem (Connelly, Demaine, Rote, 2003)[221]
  • Cameron–Erdős conjecture (Ben J. Green, 2003, Alexander Sapozhenko, 2003)[222] [223]
  • Milnor conjecture (Vladimir Voevodsky, 2003)[224]
  • Kemnitz's conjecture (Reiher, 2003, di Fiore, 2003)[225]
  • Nagata's conjecture (Shestakov, Umirbaev, 2003)[226]
  • Kirillov's conjecture (Baruch, 2003)[227]
  • Poincaré conjecture (Grigori Perelman, 2002)[196]
  • Strong perfect graph conjecture (Maria Chudnovsky, Neil Robertson, Paul Seymour and Robin Thomas, 2002)[228]
  • Kouchnirenko's conjecture (Haas, 2002)[229]
  • Vaught conjecture (Knight, 2002)[230]
  • Double bubble conjecture (Hutchings, Morgan, Ritoré, Ros, 2002)[231]
  • Catalan's conjecture (Preda Mihăilescu, 2002)[232]
  • n! conjecture (Haiman, 2001)[233] (and also Macdonald positivity conjecture)
  • Kato's conjecture (Auscher, Hofmann, Lacey, McIntosh and Tchamitchian, 2001)[234]
  • Deligne's conjecture on 1-motives (Luca Barbieri-Viale, Andreas Rosenschon, Morihiko Saito, 2001)[235]
  • Modularity theorem (Breuil, Conrad, Diamond and Taylor, 2001)[236]
  • Erdős–Stewart conjecture (Florian Luca, 2001)[237]
  • Berry–Robbins problem (Atiyah, 2000)[238]
  • Erdős–Graham problem (Croot, 2000)[239]

20th century [edit]

  • Honeycomb conjecture (Thomas Hales, 1999)[240]
  • Gradient conjecture (Krzysztof Kurdyka, Tadeusz Mostowski, Adam Parusinski, 1999)[241]
  • Bogomolov conjecture (Emmanuel Ullmo, 1998, Shou-Wu Zhang, 1998)[242] [243]
  • Lafforgue's theorem (Laurent Lafforgue, 1998)[244]
  • Ganea conjecture (Iwase, 1997)[245]
  • Torsion conjecture (Merel, 1996)[246]
  • Harary's conjecture (Chen, 1996)[247]

See also [edit]

  • List of conjectures
  • List of unsolved problems in statistics
  • List of unsolved problems in computer science
  • List of unsolved problems in physics
  • Lists of unsolved problems
  • Open Problems in Mathematics
  • The Great Mathematical Problems
  • Scottish Book

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Further reading [edit]

Books discussing problems solved since 1995 [edit]

  • Singh, Simon (2002). Fermat's Last Theorem. Fourth Estate. ISBN978-1-84115-791-7.
  • O'Shea, Donal (2007). The Poincaré Conjecture. Penguin. ISBN978-1-84614-012-9.
  • Szpiro, George G. (2003). Kepler's Conjecture. Wiley. ISBN978-0-471-08601-7.
  • Ronan, Mark (2006). Symmetry and the Monster. Oxford. ISBN978-0-19-280722-9.

Books discussing unsolved problems [edit]

  • Chung, Fan; Graham, Ron (1999). Erdös on Graphs: His Legacy of Unsolved Problems. AK Peters. ISBN978-1-56881-111-6.
  • Croft, Hallard T.; Falconer, Kenneth J.; Guy, Richard K. (1994). Unsolved Problems in Geometry . Springer. ISBN978-0-387-97506-1.
  • Guy, Richard K. (2004). Unsolved Problems in Number Theory. Springer. ISBN978-0-387-20860-2.
  • Klee, Victor; Wagon, Stan (1996). Old and New Unsolved Problems in Plane Geometry and Number Theory . The Mathematical Association of America. ISBN978-0-88385-315-3.
  • du Sautoy, Marcus (2003). The Music of the Primes: Searching to Solve the Greatest Mystery in Mathematics . Harper Collins. ISBN978-0-06-093558-0.
  • Derbyshire, John (2003). Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics . Joseph Henry Press. ISBN978-0-309-08549-6.
  • Devlin, Keith (2006). The Millennium Problems – The Seven Greatest Unsolved* Mathematical Puzzles Of Our Time. Barnes & Noble. ISBN978-0-7607-8659-8.
  • Blondel, Vincent D.; Megrestski, Alexandre (2004). Unsolved problems in mathematical systems and control theory. Princeton University Press. ISBN978-0-691-11748-5.
  • Ji, Lizhen; Poon, Yat-Sun; Yau, Shing-Tung (2013). Open Problems and Surveys of Contemporary Mathematics (volume 6 in the Surveys in Modern Mathematics series) (Surveys of Modern Mathematics). International Press of Boston. ISBN978-1-57146-278-7.
  • Waldschmidt, Michel (2004). "Open Diophantine Problems" (PDF). Moscow Mathematical Journal. 4 (1): 245–305. arXiv:math/0312440. doi:10.17323/1609-4514-2004-4-1-245-305. ISSN 1609-3321. S2CID 11845578. Zbl 1066.11030.
  • Mazurov, V. D.; Khukhro, E. I. (1 Jun 2015). "Unsolved Problems in Group Theory. The Kourovka Notebook. No. 18 (English version)". arXiv:1401.0300v6 [math.GR].
  • The Sverdlovsk Notebook is a collection of unsolved problems in semigroup theory.[1] [2]
  • Formulation of 50 {\displaystyle 50} unresolved problems for infinite Abelian groups are depicted in the book[3]
  • The list of 17 {\displaystyle 17} unresolved problems for Combinatorial Geometry are depicted in the book.[4]
  • Several dozens of unresolved problems for Combinatorial Geometry are depicted in the book.[5]
  • Many unresolved problems for Graph theory are depicted in the article.[6]
  • The list of several unresolved problems converning Maler Conjecture are depicted in the book.[7]

External links [edit]

  • 24 Unsolved Problems and Rewards for them
  • List of links to unsolved problems in mathematics, prizes and research
  • Open Problem Garden The collection of open problems in mathematics build on the principle of user editable ("wiki") site
  • AIM Problem Lists
  • Unsolved Problem of the Week Archive. MathPro Press.
  • Ball, John M. "Some Open Problems in Elasticity" (PDF).
  • Constantin, Peter. "Some open problems and research directions in the mathematical study of fluid dynamics" (PDF).
  • Serre, Denis. "Five Open Problems in Compressible Mathematical Fluid Dynamics" (PDF).
  • Unsolved Problems in Number Theory, Logic and Cryptography
  • 200 open problems in graph theory
  • The Open Problems Project (TOPP), discrete and computational geometry problems
  • Kirby's list of unsolved problems in low-dimensional topology
  • Erdös' Problems on Graphs
  • Unsolved Problems in Virtual Knot Theory and Combinatorial Knot Theory
  • Open problems from the 12th International Conference on Fuzzy Set Theory and Its Applications
  • List of open problems in inner model theory
  • Aizenman, Michael. "Open Problems in Mathematical Physics".
  • Barry Simon's 15 Problems in Mathematical Physics
  1. ^ The Sverdlovsk Notebook: collects unsolved problems in semigroup theory, Ural State University, 1979
  2. ^ The Sverdlovsk Notebook: collects unsolved problems in semigroup theory, Ural State University, 1989
  3. ^ Fuks 1974, pp. 47, 88, 116, 134, 158, 159, 186, 210, 242, 243, 292, 318. sfn error: no target: CITEREFFuks1974 (help)
  4. ^ Boltiansky 1965, p. 83. sfn error: no target: CITEREFBoltiansky1965 (help)
  5. ^ Grunbaum 1971, p. 6. sfn error: no target: CITEREFGrunbaum1971 (help)
  6. ^ V. G. Vizing Some unresolved problems for Graph theory // Russian Mathematical Surveys, 23:6(144) (1968), 117–134; Russian Math. Surveys, 23:6 (1968), 125–141
  7. ^ Sprinjuk 1967, pp. 150–154. sfn error: no target: CITEREFSprinjuk1967 (help)

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