Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Identity for Kernel Ridge Regression   This paper derives an identity connecting the square loss of ridge regression
in on-line mode with the loss of the retrospectively best regressor. Some
corollaries about the properties of the cumulative loss of on-line ridge
regression are also obtained.

13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga