Lowest possible vertex density in a graph What is the least amount of vertexes possible in a graph where the distance from any point on or around the graph to any vertex is at most $1$ unit of length?
For example, a map covering $10$ by $10 \text{ km}$ and you want to have waystations distributed on the map so that each waystation is at most $5\text{ km}$ away from any point.
This is the complete graph of arbitrary $V$:
This is the complete graph of arbitrary $V$: