MathDB
The least possible number of vertices -[UKRMO 2009 Grade 11]

Source:

January 23, 2011
pigeonhole principlegraph theorycombinatorics proposedcombinatorics

Problem Statement

Let GG be a connected graph, with degree of all vertices not less then m3m \geq 3, such that there is no path through all vertices of GG being in every vertex exactly once. Find the least possible number of vertices of G.G.