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Diff — Graph theory

Revision #1275 → #1763 · back to history

modifiedGraph4f2378b011ef
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mathlib.match_kindexact
noteUndirected graphs are formalized as SimpleGraph (simple) and Graph (general multigraph in Mathlib.Combinatorics.Graph.Basic).Undirected simple graphs are formalized as SimpleGraph; general multigraphs as Graph in Mathlib.Combinatorics.Graph.Basic.
modifiedDirected graph7f720204ad7d
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noteQuiver formalizes directed graphs (as a directed multigraph, generalizing simple digraphs).Quiver formalizes directed (multi)graphs, generalizing simple digraphs.
modifiedMultigraph130fe0299f11
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noteGraph α β models multigraphs with vertex/edge sets and incidence data allowing parallel edges and loops.Graph α β models multigraphs with parallel edges and loops via incidence data.
addedSeven Bridges of Königsberg7c85f097c531
addedEuler's polyhedron formula5812ff771c1d
modifiedGraph coloring4643bb1fdce2
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mathlib.moduleMathlib.Combinatorics.SimpleGraph.Coloring.VertexColoringMathlib.Combinatorics.SimpleGraph.Coloring.Vertex
noteProper vertex colorings are formalized as SimpleGraph.Coloring with Colorable and chromaticNumber.Proper vertex colorings are formalized as SimpleGraph.Coloring with associated Colorable and chromaticNumber.
modifiedFour-color theoremc71be2aa0255
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noteThe four-color theorem is not formalized in Mathlib (it requires planarity).The four-color theorem is not formalized in Mathlib (no planarity).
addedFive-color theorem9610fb590b56
modifiedSpectral graph theory51b6f2ea6871
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noteAdjacency/Laplacian matrices and some spectral results (positive semidefiniteness, connected-component kernel dimension) are formalized, but not a general spectral theory.Adjacency/Laplacian matrices and some spectral results exist, but not a general spectral theory.
modifiedTutte polynomial0ae150459db7
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noteThe Tutte polynomial is absent (the file Tutte.lean concerns Tutte's matching theorem, not the polynomial).The Tutte polynomial is absent from Mathlib (the existing Tutte material concerns Tutte's matching theorem).
addedHadwiger–Nelson problema31d1bf42e3a
modifiedUnit disk graph80e97e4010ec
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noteUnit disk graphs are not defined (Mathlib's UnitDistance graphs are a different family).Unit disk graphs are not defined in Mathlib (UnitDistance graphs are a different family).
modifiedTurán's theorem3ec185ee2226
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noteTurán's theorem is formalized in full as an isomorphism characterization of extremal Kr+1-free graphs.Turán's theorem is formalized as an isomorphism characterization of extremal Kr+1-free graphs.
addedGraph homomorphism18a894b8538a
modifiedSzemerédi's regularity lemma9d1ddc4ac479
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mathlib.declSimpleGraph.szemeredi_regularityszemeredi_regularity
noteSzemerédi's regularity lemma is formalized as szemeredi_regularity giving an ε-uniform equipartition.Szemerédi's regularity lemma is formalized as szemeredi_regularity giving an ε-uniform equipartition of bounded size.
modifiedUniform spanning tree3ba17df2bb3a
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noteUniform spanning trees (and spanning trees as a counted object) are not formalized in Mathlib.Uniform spanning trees are not formalized in Mathlib.
modifiedLaplacian matrix2ef0353d06c3
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noteThe Laplacian is formalized as SimpleGraph.lapMatrix = degMatrix - adjMatrix.The Laplacian is formalized as SimpleGraph.lapMatrix = degMatrix − adjMatrix.
addedErdős–Faber–Lovász conjectureabfdeb227da2
addedTotal coloring conjecture8b59c6408b49
addedList coloring conjecture8d2bac80a2b6
addedHadwiger conjectured7f15473e2b6
addedHamiltonian path problemd2c6cfd91cc2
addedMinimum spanning treeb3b92a03926d
addedShortest path problem453bff27f150
addedTraveling salesman problemdb95911c732c