crowlogic / arb4j

arb4j is a Java API for the arbitrary precision ball arithmetic library found at http://arblib.org
Other
1 stars 0 forks source link

Resolution of the identity #524

Closed crowlogic closed 1 month ago

crowlogic commented 1 month ago

Resolution of the Identity in RKHS

  1. Expression of the Identity: The resolution of the identity can be expressed as:

    I = \sum_{k} \phi_k(x) \phi_k^*(y)

    where \phi_k are the eigenfunctions (basis functions) of the kernel associated with the RKHS, and I is the identity operator.

  2. Convergence and Function Approximation:

    • The statement that I converges to the identity operator means that for any function f in the RKHS, you can represent it as:

    f(x) = \sum_{k} \langle f, \phi_k \rangle \phi_k(x)

    In this context, the sums converge in the norm of the RKHS, and as you include more terms from your basis, you get closer to the true function f(x).

  3. Relation to the Kernel:

    • If the kernel itself can be expressed in terms of this basis, it means that the kernel is representable as:

    K(x, y) = \sum_{k} \lambda_k \phi_k(x) \phi_k^*(y)

    where \lambda_k are the eigenvalues corresponding to⬤