Conformally Invariant Variational Problems. - SAM
Conformally Invariant Variational Problems. - SAM
Conformally Invariant Variational Problems. - SAM
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If A is almost everywhere invertible, and if it has the bound<br />
‖A‖ L∞ (D 2 ) +‖A −1 ‖ L∞ (D 2 ) < +∞ ,<br />
(VIII.12)<br />
then u is a solution of the Schrödinger system (VIII.6) if and<br />
only if it satisfies the conservation law<br />
div(A∇u−B∇ ⊥ u) = 0 .<br />
(VIII.13)<br />
If (VIII.13) holds, then u ∈ W 1,p<br />
loc (D2 ,R m ) for any 1 ≤ p <<br />
+∞, and therefore u is Hölder continuous in the interior of D 2 ,<br />
C 0,α<br />
loc (D2 ) for any α < +∞ .<br />
✷<br />
We note that the conservation law (VIII.13), when it exists,<br />
generalizes the conservation laws previously encountered in the<br />
study of problems with symmetry, namely:<br />
1) In the case of the constant mean curvature equation, the<br />
conservation law (VII.1) is (VIII.13) with the choice<br />
A ij = δ ij ,<br />
and<br />
⎛<br />
B = ⎜<br />
⎝<br />
0 −Hu 3 Hu 2<br />
Hu 3 0 −Hu 1<br />
⎞<br />
⎟<br />
⎠<br />
−Hu 2 Hu 1 0<br />
2) In the case of S n -valued harmonic maps, the conservation<br />
law (VII.25) is (VIII.13) for<br />
A ij = δ ij ,<br />
and B = (B i j ) with ∇ ⊥ B i j = u i ∇u j −u j ∇u i .<br />
Theultimatepartofthissectionwillbedevotedtoconstructing<br />
A and B, for any given antisymmetric Ω, with sufficiently<br />
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