Kees Dullemond & Kasper Peeters - Heidelberg University

This index notation is also applicable to other manipulations, for instance the inner product. Take two vectors~v and ~w, then we define the inner product as ~v· ~w := v 1w 1 +···+v nw = n ∑ µ=1 v µw. (1.7) (We will return extensively to the inner product. Here it is just as an example of the power of the index notation).

  Notation