On the algebraic properties of the ${H}_{\frac{n}{2},\frac{1}{2}}$ spaces
Séminaire Équations aux dérivées partielles (Polytechnique) (1997-1998), Talk no. 7, 9 p.

We investigate the multiplicative properties of the spaces ${H}^{\frac{n}{2},\frac{1}{2}}$ As in the case of the classical Sobolev spaces ${H}^{\frac{n}{2}}$ this space does not form an algebra. We investigate instead the space ${H}^{\frac{n}{2}}\cap {L}^{\infty }$ , more precisely a subspace of it formed by products of solutions of the homogeneous wave equation with data in ${H}^{\frac{n}{2}}$.

@article{SEDP_1997-1998____A7_0,
author = {Klainerman, Sergiu and Machedon, Matei},
title = {On the algebraic properties of the $H\_{\frac{n}{2},{\frac{1}{2}}}$ spaces},
journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique)},
publisher = {Centre de math\'ematiques Laurent Schwartz, \'Ecole polytechnique},
year = {1997-1998},
note = {talk:7},
mrnumber = {1660520},
zbl = {1064.46501},
language = {en},
url = {http://www.numdam.org/item/SEDP_1997-1998____A7_0}
}

Klainerman, Sergiu; Machedon, Matei. On the algebraic properties of the $H_{\frac{n}{2},{\frac{1}{2}}}$ spaces. Séminaire Équations aux dérivées partielles (Polytechnique) (1997-1998), Talk no. 7, 9 p. http://www.numdam.org/item/SEDP_1997-1998____A7_0/

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