The following statements are about the chromatic number χ(G) and the chromatic index χ′(G) of graphs. We use Δ(G) for the maximum degree of G. Are the following statements true or false?
1. If a graph contains a vertex of degree 7, then the chromatic index of the graph is at least 7.
2. For all n≥3, χ′(Cn)=Δ(Cn).
3. For any cycle, the chromatic index is equal to the chromatic number.
4. If every vertex of a graph has a degree at most 5, then the chromatic index of the graph is at least 5.