- Part 1:

- Part 2:

- Part 3:

There are other sources of information on index notation available on the web as well. Two useful ones are:

http://solidmechanics.org/text/AppendixC/AppendixC.htm

and

http://www.ees.nmt.edu/outside/Geop/Classes/GEOP523/Docs/index-notation.pdf

Index notation is a very valuable way of describing and manipulating vectors and tensors, if a bit weird at first. Once you've gotten the basic rules down, it makes many calculations far simpler!