Projection matrix
= Projection matrix
{wiki=Projection_matrix}
A projection matrix is a square matrix that transforms a vector into its projection onto a subspace. In the context of linear algebra, projections are used to reduce the dimensionality of data or to find the closest point in a subspace to a given vector. \#\#\# Key Properties of Projection Matrices: 1. **Idempotent**: A matrix \\( P \\) is a projection matrix if \\( P^2 = P \\).