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Hamzi - Eurandom

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Reproducing Kernel Hilbert Spaces<br />

• In learning theory, the minimization is taken over functions from a<br />

hypothesis space often taken to be a ball of a RKHS HK associated to<br />

Mercer kernel K, and the function fs that minimizes the empirical error Es<br />

is<br />

m∑<br />

fs = cjK(x, xj),<br />

where the coefficients (cj) m j=1<br />

λ m ci +<br />

j=1<br />

is solved by the linear system<br />

m∑<br />

K(xi, xj)cj = yi, i = 1, · · · m,<br />

j=1<br />

and fs is taken as an approximation of the regression function fρ.<br />

• We call learning the process of approximating the unknown function f<br />

from random samples on Z.<br />

. . . . . .<br />

Boumediene <strong>Hamzi</strong> (Imperial College) On Control and RDS in RKHS June 4th, 2012 26 / 55

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