In mathematics, a linear map (also called a linear transformation or linear operator) is a function between two vector spaces that preserves the operations of vector addition and scalar multiplication.
The term linear transformation is especially used for linear maps from a vector space to itself (endomorphisms).
Let V and W be vector spaces over the same field K. A function f : V → W is said to be a linear map if for any two vectors x and y in V and any scalar a in K, the following two conditions are satisfied:
- - additivity,
- - homogenity.
This is equivalent to requiring that for any vectors x1, ..., xm and scalars a1, ..., am, the equality