The numbers represent how many handshakes each person has, which in a graph is known as the “degree” of the vertex: It’s the number of edges that are connected to that vertex. The graphs that ...

Although the puzzles are often billed as requiring no math ... vertex is colored and no two connected vertices have the same color, the coloring is called “proper.” Thus, in the language of ...

In math, as in life, small choices can have big consequences ... Let’s walk through the argument using the following triangle-free graph as an example. Start by picking any vertex in the graph and ...

the vertex is a maximum turning point We can identify these properties from a quadratics graph or equation.

That is, each edge receives two ``half colors'' so that no half color is repeated at a vertex ... anti-blocking pairs of polyhedra, Math. Programming 1 (1971) 168-194. [2] P.D. Seymour, On ...