1. ## Chinese postman problem

Hey everybody!

I am no maths student, I am studying business administration and for logistics we have an exercise which i can't even begin with so i would appreciate any help. I have to say that the professor never even told us about this problem but somehow we have to figure this out on or own. Thanks in advance!

We have a network 8x8 of a big chessboard. The 81 grid points are the crossroads. The crossroads are linked with the neighboring crossroads through edges of 1 m length horizontally and vertically. The horizontal streets can be crossed in both directions. The vertical 1st, 3rd, 5th, 7th and 9th streets from up to down and the 2nd, 4th, 6th, 8th from down to up. In this described graph can only the four fields in the centre of the chessboard turn clockwise to 90 degrees including the street orientation. The minimum number of visited edges of the optimal solution of this graph's chinese postman problem's is then:

22

23

24

2. ## Re: Chinese postman problem

Hey yan1990.

You are probably going to have to do an induction related approach for this problem.

Have you considered the case when you have n^2 squares and then (n+1)^2 squares?

3. ## Re: Chinese postman problem

We have 64 squares...But i don't understand how induction is here the solution

5. ## Re: Chinese postman problem

Induction is when you look at an isolated case for n and then try and find a relation for n+1.

My thinking is that if the rules are the same for each square route (so think four nodes and edges connecting each adjacent "node") then one could find an inductive argument of the path taken given the less complex region.

So if you have say n = 1 you get a point in the left hand corner. A case for n = 2 gives four nodes and the edges connecting them. n = 3 gives nine nodes and so on up until you do the whole 8x8 board with all edges.

This is a common technique used to prove a lot of things in mathematics.