Displaying similar documents to “Polynomial asymptotics and approximation of Sobolev functions”

Pointwise inequalities for Sobolev functions and some applications

Bogdan Bojarski, Piotr Hajłasz (1993)

Studia Mathematica

Similarity:

We get a class of pointwise inequalities for Sobolev functions. As a corollary we obtain a short proof of Michael-Ziemer’s theorem which states that Sobolev functions can be approximated by C m functions both in norm and capacity.

Theory of Bessel potentials. II

Robert Adams, Nachman Aronszajn, K. T. Smith (1967)

Annales de l'institut Fourier

Similarity:

Dans cette partie de la théorie des potentiels besseliens on considère les restrictions de potentiels de la classe P a ( R n ) aux domaines ouverts D R n . On cherche à caractériser de manière intrinsèque la classe P a ( D ) ainsi obtenue. On attaque ce problème en définissant de manière directe (§ 2) une classe P ˇ a ( D ) P a ( D ) qui, pour des domaines assez réguliers, est égale à P a ( D ) . L’égalité P a ( D ) = P a ( D ) est équivalente à l’existence d’un opérateur-extension E : P ˇ a ( D ) P a ( R n ) , linéaire et continu, tel que E u soit une extension...

Best constants and asymptotics of Marcinkiewicz-Zygmund inequalities

Andreas Defant, Marius Junge (1997)

Studia Mathematica

Similarity:

We determine the set of all triples 1 ≤ p,q,r ≤ ∞ for which the so-called Marcinkiewicz-Zygmund inequality is satisfied: There exists a constant c≥ 0 such that for each bounded linear operator T : L q ( μ ) L p ( ν ) , each n ∈ ℕ and functions f 1 , . . . , f n L q ( μ ) , ( ʃ ( k = 1 n | T f k | r ) p / r d ν ) 1 / p c T ( ʃ ( k = 1 n | f k | r ) q / r d μ ) 1 / q . This type of inequality includes as special cases well-known inequalities of Paley, Marcinkiewicz, Zygmund, Grothendieck, and Kwapień. If such a Marcinkiewicz-Zygmund inequality holds for a given triple (p,q,r), then we calculate the best constant c ≥ 0 (with the...