On Bernstein- and Marcinkiewicz-type inequalities on multivariate $C^\alpha$-domains

We prove new Bernstein and Markov type inequalities in $L^p$ spaces associated with the normal and the tangential derivatives on the boundary of a general compact $C^\alpha$-domain with $1\leq \alpha\leq 2$. These estimates are also applied to establish Marcinkiewicz type inequalities for discretization of $L^p$ norms of algebraic polynomials on $C^\alpha$-domains with asymptotically optimal number of function samples used.