"minimal counterexample" - related articles and key terms

Related terms: four colours   suffice   vertex of degree   true for all   we will prove   every planar   color theorem   minimal element   five colors   planar graphs   weisstein   unavoidable   discharging   graph coloring   triangulated   counterexample   empty list   four color theorem   fredrick   number of vertices   four color   haken   reducible   kempe   arbitrarily   proving

Wikipedia sources: Four color theorem   Structural induction


Context for words: minimal   counterexample