EntityQ1128435· pop 7· linked from 28 articlesHadwiger conjectureSign in to saveconjecture that all graphs requiring k or more colors contain a k-vertex complete minorConnectionsgraph coloringEntityglossary of graph theory termsEntityminor graphEntityInternational Standard Book NumberEntitydigital object identifierEntityPaul ErdősEntitygraph theoryEntitygraphEntityQ118398Entityfour color theoremEntitydisjoint setsEntitybig O notationEntitycomplete graphEntityQ22908627Entitybipartite graphEntitylist of unsolved problems in mathematicsEntityHandle SystemEntitycontrapositionEntityPetersen graphEntityMathematical ReviewsEntityCategoriesConjecturesGraph coloringGraph minor theoryUnsolved problems in graph theory