Linear algebra

Basis and span

The span of vectors contains all their linear combinations. A basis is an independent set that spans a vector space.

Ask the Linear algebra assistant 1 min read · Updated September 9, 2026

Definition

The span of vectors contains all their linear combinations. A basis is an independent set that spans a vector space.

Intuition

A basis is a complete coordinate system without redundant directions.

Worked example

(1, 0) and (0, 1) form a basis of the plane. The single vector (1, 1) spans only a line.

The math

Every vector has a unique linear combination in a chosen basis. The number of basis vectors is the dimension.

In machine learning

Choose a basis to simplify a transformation, compress a representation, or interpret feature directions.

Go deeper

Sources

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