Norm

The norm of a mathematical object is a quantity that in some (possibly abstract) sense describes the length, size, or extent of the object.

In mathematics, the norm of a vector is its length.

A norm is a function from a vector space over real or complex numbers to nonnegative real numbers.

It will satisfy certain properties.

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A Euclidian Norm for an n-dimensional vector:

||x||_2 =\sqrt{x_1^2 + x_2^2 + ... + x_n^2}