Open Problems


Titlesort iconAuthor(s)Imp.¹Rec.²Area » Topic » SubtopicPosted by
Mixing Circular ColouringsBrewster; Noel1Graph Theory » Coloring » Vertex coloringJon Noel
Monadic second-order logic with cardinality predicatesCourcelle✭✭0Logic » Finite Model Theorydberwanger
Monochromatic empty triangles✭✭✭0Geometrymdevos
Monochromatic reachability in arc-colored digraphsSands; Sauer; Woodrow✭✭✭0Graph Theory » Directed Graphsfhavet
Monochromatic reachability or rainbow trianglesSands; Sauer; Woodrow✭✭✭0Graph Theory » Directed Graphs » Tournamentsmdevos
Monochromatic vertex colorings inherited from Perfect Matchings✭✭✭1Graph TheoryMario Krenn
Monotone 4-term Arithmetic ProgressionsDavis; Entringer; Graham; Simmons✭✭0Combinatoricsvjungic
MSO alternation hierarchy over picturesGrandjean✭✭0Logic » Finite Model Theorydberwanger
Nearly spanning regular subgraphsAlon; Mubayi✭✭✭0Graph Theory » Basic G.T.mdevos
Negative association in uniform forestsPemantle✭✭0Graph Theory » Probabilistic G.T.mdevos
Non-edges vs. feedback edge sets in digraphsChudnovsky; Seymour; Sullivan✭✭✭0Graph Theory » Directed Graphsmdevos
Nonrepetitive colourings of planar graphsAlon N.; Grytczuk J.; Hałuszczak M.; Riordan O.✭✭0Graph Theory » Coloring » Vertex coloringDavid Wood
Nonseparating planar continuum✭✭0Topologyporton
Number of Cliques in Minor-Closed ClassesWood✭✭0Graph TheoryDavid Wood
Obstacle number of planar graphsAlpert; Koch; Laison1Graph TheoryAndrew King
Odd cycles and low oddness✭✭0Graph TheoryGagik
Odd incongruent covering systemsErdos; Selfridge✭✭✭0Number Theory » Combinatorial N.T.Robert Samal
Odd perfect numbersAncient/folklore✭✭✭1Number Theoryazi
Odd-cycle transversal in triangle-free graphsErdos; Faudree; Pach; Spencer✭✭0Graph Theory » Extremal G.T.fhavet
Olson's ConjectureOlson✭✭0Number Theory » Combinatorial N.T.mdevos
One-way functions exist✭✭✭✭0Theoretical Comp. Sci. » Complexityporton
Order-invariant queriesSegoufin✭✭0Logic » Finite Model Theorydberwanger
Oriented chromatic number of planar graphs✭✭0Graph Theory » Coloring » Vertex coloringRobert Samal
Oriented trees in n-chromatic digraphsBurr✭✭✭0Graph Theory » Directed Graphsfhavet
Outer reloid of restricted funcoidPorton✭✭0Topologyporton
Outward reloid of composition vs composition of outward reloidsPorton✭✭0Topologyporton
P vs. BPPFolklore✭✭✭0Theoretical Comp. Sci. » Complexity » DerandomizationCharles R Great...
P vs. NPCook; Levin✭✭✭✭0Theoretical Comp. Sci. » Algorithmszitterbewegung
P vs. PSPACEFolklore✭✭✭0Theoretical Comp. Sci. » Complexitycwenner
Packing T-joinsDeVos✭✭0Graph Theory » Coloring » Edge coloringmdevos
Partial List ColoringAlbertson; Grossman; Haas✭✭✭0Graph Theory » Coloring » Vertex coloringIradmusa
Partial List ColoringIradmusa✭✭✭0Graph Theory » Coloring » Vertex coloringIradmusa
Partition of a cubic 3-connected graphs into paths of length 2.Kelmans✭✭0Graph Theory » Basic G.T. » Pathsfhavet
Partition of Complete Geometric Graph into Plane Trees✭✭0GeometryDavid Wood
Partitioning edge-connectivityDeVos✭✭0Graph Theory » Basic G.T. » Connectivitymdevos
Partitioning the Projective PlaneNoel✭✭1GeometryJon Noel
Partitionning a tournament into k-strongly connected subtournaments.Thomassen✭✭0Graph Theory » Directed Graphs » Tournamentsfhavet
Pebbling a cartesian productGraham✭✭✭0Graph Theorymdevos
Pentagon problemNesetril✭✭✭0Graph Theory » Coloring » HomomorphismsRobert Samal
Perfect 2-error-correcting codes over arbitrary finite alphabets.✭✭0Combinatorics » Codesdavidcullen
Perfect cuboid✭✭0Number Theory » Computational N.T.tsihonglau
Petersen coloring conjectureJaeger✭✭✭0Graph Theory » Coloring » Edge coloringmdevos
Point sets with no empty pentagonWood1GeometryDavid Wood
Polignac's Conjecturede Polignac✭✭✭0Number TheoryHugh Barker
Primitive pythagorean n-tuple tree✭✭0Number Theorytsihonglau
PTAS for feedback arc set in tournamentsAilon; Alon✭✭0Graph Theory » Graph Algorithmsfhavet
Quartic rationally derived polynomialsBuchholz; MacDougall✭✭✭0Number Theorymdevos
r-regular graphs are not uniquely hamiltonian.Sheehan✭✭✭0Graph Theory » Basic G.T. » CyclesRobert Samal
Rainbow AP(4) in an almost equinumerous coloringConlon✭✭0Combinatoricsvjungic
Ramsey properties of Cayley graphsAlon✭✭✭0Graph Theory » Algebraic G.T.mdevos
Syndicate content