Kernel Matrix


<> means [Vector Similarity](https://texonom.com/vector-similarity-846675a408e74235acc836302110ab07) and $\phi(x)$ means vector kernel mapping function
$$K_{nm} = K_{mn} =  K(x_n, x_m) = <\phi(x_n), \phi(x_m)>$$
- If K is a valid kernel, K must be symmetric
- If K is a valid kernel, K must be semi-definite
### Kernel Matrix Notion
|Title|
|:-:|
|[Mercer Kernel Theorem](https://texonom.com/mercer-kernel-theorem-cebcf7555bf44413907751aa58633ee0)|









