ABSTRACT
For a vector, the notation xt denotes the transpose; if x is a column vector, then xt is a row vector:
Vectors and matrices are added component-by-component. For example,
matrices are added similarly. There are three possible ways to define the product of two vectors: the inner (or
dot) product, the cross product7, and the outer product, which pro-
duce a scalar, a vector, and a matrix, respectively. The dot product is the most familiar:
where x and y are vectors of length n. Note that x·y is a scalar. We will encounter the outer product in §5.3.
