Open Problems


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Finite entailment of Positive Horn logicMartin✭✭0Logic » Finite Model TheoryLucSegoufin
Finding k-edge-outerplanar graph embeddingsBentz✭✭0Graph Theoryjcmeyer
Few subsequence sums in Z_n x Z_nBollobas; Leader✭✭0Number Theory » Combinatorial N.T.mdevos
Fat 4-polytopesEppstein; Kuperberg; Ziegler✭✭✭0Geometry » Polytopesmdevos
Faithful cycle coversSeymour✭✭✭0Graph Theory » Basic G.T. » Cyclesmdevos
Extremal problem on the number of tree endomorphismZhicong Lin✭✭1Graph Theory » Extremal G.T.shudeshijie
Extremal $4$-Neighbour Bootstrap Percolation in the HypercubeMorrison; Noel✭✭0CombinatoricsJon Noel
Extension complexity of (convex) polygons✭✭0Geometry » PolytopesDOT
Exponential Algorithms for KnapsackLipton✭✭1Theoretical Comp. Sci. » Algorithmsdick lipton
Exact colorings of graphsErickson✭✭0Graph TheoryMartin Erickson
Every prism over a 3-connected planar graph is hamiltonian.Kaiser; Král; Rosenfeld; Ryjácek; Voss✭✭0Graph Theory » Basic G.T. » Cyclesfhavet
Every metamonovalued reloid is monovaluedPorton✭✭0Topologyporton
Every metamonovalued funcoid is monovaluedPorton✭✭0Topologyporton
Every 4-connected toroidal graph has a Hamilton cycleGrunbaum; Nash-Williams✭✭0Graph Theory » Topological G.T.fhavet
Even vs. odd latin squaresAlon; Tarsi✭✭✭0Combinatoricsmdevos
Euler-Mascheroni constant✭✭✭0Number Theory » Analytic N.T.Juggernaut
Erdős–Straus conjectureErdos; Straus✭✭1Number TheoryACW
Erdős–Faber–Lovász conjectureErdos; Faber; Lovasz✭✭✭0Graph Theory » Coloring » Vertex coloringJon Noel
Erdös-Szekeres conjectureErdos; Szekeres✭✭✭0Geometrymdevos
Erdős-Posa property for long directed cyclesHavet; Maia✭✭0Graph Theory » Directed Graphsfhavet
Equality in a matroidal circumference boundOxley; Royle✭✭0Combinatorics » Matroid TheoryGordon Royle
End-Devouring RaysGeorgakopoulos1Graph Theory » Infinite GraphsAgelos
Elementary symmetric of a sum of matrices✭✭✭0Algebrarscosa
Edge-Unfolding Convex PolyhedraShephard✭✭0GeometryErik Demaine
Edge-disjoint Hamilton cycles in highly strongly connected tournaments.Thomassen✭✭0Graph Theory » Directed Graphs » Tournamentsfhavet
Edge-Colouring Geometric Complete GraphsHurtado✭✭1GeometryDavid Wood
Edge-antipodal colorings of cubesNorine✭✭0Combinatorics » Ramsey Theorymdevos
Edge Reconstruction ConjectureHarary✭✭✭0Graph Theorymelch
Edge list coloring conjecture✭✭✭0Graph Theory » Coloring » Edge coloringtchow
Earth-Moon ProblemRingel✭✭1Graph Theory » Coloring » Vertex coloringfhavet
Durer's ConjectureDurer; Shephard✭✭✭1Geometry » Polytopesdmoskovich
Drawing disconnected graphs on surfacesDeVos; Mohar; Samal✭✭0Graph Theory » Topological G.T. » Crossing numbersmdevos
Double-critical graph conjectureErdos; Lovasz✭✭0Graph Theory » Coloring » Vertex coloringDFR
Domination in plane triangulationsMatheson; Tarjan✭✭0Graph Theory » Topological G.T.mdevos
Domination in cubic graphsReed✭✭0Graph Theory » Basic G.T.mdevos
Does the chromatic symmetric function distinguish between trees?Stanley✭✭0Graph Theory » Algebraic G.T.mdevos
Do any three longest paths in a connected graph have a vertex in common? Gallai✭✭0Graph Theoryfhavet
Divisibility of central binomial coefficientsGraham✭✭1Number Theory » Combinatorial N.T.maxal
Dividing up the unrestricted partitionsDavid S.; Newman✭✭0CombinatoricsDavidSNewman
Distribution and upper bound of mimic numbersBhattacharyya✭✭1Number Theory » Analytic N.T.facility_cttb@i...
Discrete Logarithm Problem✭✭✭0Theoretical Comp. Sci. » Complexitycplxphil
Directed path of length twice the minimum outdegreeThomassé✭✭✭0Graph Theory » Directed Graphsfhavet
Direct proof of a theorem about compact funcoidsPorton✭✭0Topologyporton
Dirac's ConjectureDirac✭✭0GeometryDavid Wood
Diophantine quintuple conjecture✭✭1Number Theorymaxal
Ding's tau_r vs. tau conjectureDing✭✭✭0Combinatorics » Optimizationmdevos
Diagonal Ramsey numbersErdos✭✭✭✭0Combinatorics » Ramsey Theorymdevos
Dense rational distance sets in the planeUlam✭✭✭0Geometrymdevos
Degenerate colorings of planar graphsBorodin✭✭✭0Graph Theory » Topological G.T. » Coloringmdevos
Decomposition of completions of reloidsPorton✭✭0Topologyporton
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