Let Ω⊂Rn\Omega \subset {\mathbb R}^n be a bounded starshaped domain and consider the energy functional F[u;Ω]:=∫ΩF(∇u(x)) dx,{\mathbb F}[u; \Omega]:= \int_\Omega {\bf F}(\nabla u(x)) \, dx, over the space of measure preserving maps Ap(Ω)={u∈ξˉx+W01,p(Ω,Rn):det⁡∇u=1 a.e. in Ω},{\mathcal A}_p(\Omega)=\bigg\{u \in \bar \xi x + W_0^{1,p}(\Omega, {\mathbb R}^n): \det \nabla u = 1 \text{ $a.e.$ in $\Omega$} \bigg\}, with p∈[1,∞[p \in [1, \infty[, ξˉ∈Mn×n\bar \xi \in {\mathbb M}_{n \times n} and det⁡ξˉ=1\det \bar \xi =1. In this short note we address the question of uniqueness for solutions of the corresponding system of Euler-Lagrange equations. In particular we give a new proof of the celebrated result of R. J. Knops and C. A. Stuart [Arch. Rational Mech. Anal. 86, No. 3 (1984) 233–249] using a method based on comparison with homogeneous degree-one extensions as introduced by the second author in his recent paper "Quasiconvexity and uniqueness of stationary points in the multi-dimensional calculus of variations" [Proc. Amer. Math. Soc. 131, (2003) 3101–3107]

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Mohammad Sadegh Shahrokhi-Dehkordi

Department of Mathematics, University of Sussex, Falmer BN1 9RF, England

  1. J. M. Ball: Convexity conditions and existence theorems in nonlinear elasticity, Arch. Ration. Mech. Anal. 63 (1977) 337–403.https://doi.org/10.1007/BF00279992Google Scholar
  2. B. Dacarogna: Direct Methods in the Calculus of Variations, Applied Mathematical Sciences 78, Springer, Berlin (1988).Google Scholar
  3. R. J. Knops, C. A. Stuart: Quasiconvexity and uniqueness of equilibrium solutions in nonlinear elasticity, Arch. Ration. Mech. Anal. 86(3) (1984) 233–249.https://doi.org/10.1007/BF00281557Google Scholar
  4. M. S. Shahrokhi-Dehkordi, A. Taheri: Generalised twists, stationary loops, and the Dirichlet energy over a space of measure preserving maps, Calc. Var. Partial Differ. Equ. 35(2) (2009) 191–213.https://doi.org/10.1007/s00526-008-0202-5Google Scholar
  5. M. S. Shahrokhi-Dehkordi, A. Taheri: Generalised twists, SO(n) and the p-energy on a space of measure preserving maps, Ann. Inst. H. Poincaré C, Anal. Non Linéaire 26(5) (2009) 1897–1924.https://doi.org/10.1016/j.anihpc.2009.03.003Google Scholar
  6. A. Taheri: Quasiconvexity and uniqueness of stationary points in the multi-dimensional calculus of variations, Proc. Amer. Math. Soc. 131(10) (2003) 3101–3107.https://doi.org/10.1090/S0002-9939-03-06852-7Google Scholar
  7. A. Taheri: Minimizing the Dirichlet energy over a space of measure preserving maps, Topol. Methods Nonlinear Anal. 33(1) (2009) 179–204.https://doi.org/10.12775/TMNA.2009.013Google Scholar
  8. A. Taheri: Stationary twists and energy minimizers on a space of measure preserving self-maps, Nonlinear Anal. 71(11) (2009) 5672–5687.https://doi.org/10.1016/j.na.2009.04.050Google Scholar

M. S. Shahrokhi-Dehkordi, A. Taheri. “Quasiconvexity and Uniqueness of Stationary Points on a Space of Measure Preserving Maps.” Journal of Convex Analysis 17 (2010), No. 1, 69–79. https://doi.org/10.68381/jca17006