Item 4.1.12.a.
Let \(G\) be the graph with \(V = \{a,b,c,d,e,f\}\) and \(E = \{\{a,b\}, \{a,e\},\{b, c\}, \{b,e\}, \{c,d\}, \{c, f\}, \{d, f\}, \{e,f\}\}\text{.}\) Find \(N(a)\text{,}\) \(N[a]\text{,}\) \(N(c)\text{,}\) and \(N[c]\text{.}\)
Let \(G\) be the graph with \(V = \{a,b,c,d,e,f\}\) and \(E = \{\{a,b\}, \{a,e\},\{b, c\}, \{b,e\}, \{c,d\}, \{c, f\}, \{d, f\}, \{e,f\}\}\text{.}\) Find \(N(a)\text{,}\) \(N[a]\text{,}\) \(N(c)\text{,}\) and \(N[c]\text{.}\)