In how many distinct ways can six islands be joined by bridges so that each island can be reached from every other island...
The graph represents a salesman’s area of activity with the
shops that the salesman must visit each day. What route around the
shops has the minimum total distance?
The reader is invited to investigate changes (or permutations) in the ringing of church bells, illustrated by braid diagrams showing the order in which the bells are rung.
Euler used a graph to explain the possible routes around Old Konisberg.
He represented the land by dots and the bridges by lines joining the
dots. Think about whether there is an even number of bridges or an odd
number of bridges from each piece of land.