Solution
= Solution
Because $\widehat R(\hat h)\le\widehat R(h^*)$, adding and subtracting empirical risks and taking expectations leaves at most $E\sup_h(R(h)-\widehat R(h))$. Symmetrization and the unit-Lipschitz contraction lemma for hinge loss bound this by $2\mathcal R_n(\mathcal H)$.