TY - CHAP
T1 - Density
AU - Brezis, Haïm
AU - Mironescu, Petru
N1 - Publisher Copyright:
© 2021, Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2021
Y1 - 2021
N2 - We investigate here density questions. For real-valued Sobolev spaces, C∞(Ω¯ ; R) is dense in Ws , p(Ω; R), for any s> 0 and 1 ≤ p< ∞. This need not be true for the Sobolev spaces Ws , p(Ω; N), where N is a manifold. In particular, this is not always the case when N= S1. We present the optimal conditions on s and p so that C∞(Ω¯ ; S1) is dense in Ws , p(Ω; S1).
AB - We investigate here density questions. For real-valued Sobolev spaces, C∞(Ω¯ ; R) is dense in Ws , p(Ω; R), for any s> 0 and 1 ≤ p< ∞. This need not be true for the Sobolev spaces Ws , p(Ω; N), where N is a manifold. In particular, this is not always the case when N= S1. We present the optimal conditions on s and p so that C∞(Ω¯ ; S1) is dense in Ws , p(Ω; S1).
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U2 - 10.1007/978-1-0716-1512-6_10
DO - 10.1007/978-1-0716-1512-6_10
M3 - Chapter
AN - SCOPUS:85122467900
T3 - Progress in Nonlinear Differential Equations and Their Application
SP - 311
EP - 329
BT - Progress in Nonlinear Differential Equations and Their Application
PB - Birkhauser
ER -