Vector Norms

Overview


A vector norm is an abstraction of the concept of the length of a vector in Euclidian space.
{% length \; of \; \vec{v} = \sqrt{v_1 ^2 + ... + v_n^2} %}

Definition


A norm is a function (denoted {% ||x|| %}) that takes a vector, and returns a non-negative real number.

  1. {% ||x|| \geq 0 %}
  2. {% ||x|| = 0 %} iff {% x=0 %}
  3. {% ||\lambda x || = |\lambda| || x || %}
  4. {% || x + y || \leq ||x|| + ||y|| %}

Contents