Quadratic feature map
= Quadratic feature map
The map $x\mapsto(x_ix_j)_{i\leq j}$ embeds homogeneous quadratic forms in a linear function space of dimension $d(d+1)/2$.
= Quadratic feature map
The map $x\mapsto(x_ix_j)_{i\leq j}$ embeds homogeneous quadratic forms in a linear function space of dimension $d(d+1)/2$.