Schweizer, Ben2017-03-062017-03-062016-09-23http://hdl.handle.net/2003/35839http://dx.doi.org/10.17877/DE290R-17863We study connections between four different types of results that are concerned with vector-valued functions u : Ω→ℝ³ of class L²(Ω) on a domain Ω ⊂ ℝ³: Coercivity results in H^1(Ω) relying on div and curl, the Helmholtz decomposition, the construction of vector potentials, and the global div-curl lemma.enFriedrichs inqualitycoercivitydiv-curl lemmacompensated compactness610On Friedrichs inequality, Helmholtz decomposition, vector potentials, and the div-curl lemmaText