Talk

Hadamard's inequality in the mean

  • Martin Kružík (Czech Academy of Sciences & Czech Technical University, Prague, Czech Republic)
Augusteum - A314 Universität Leipzig (Leipzig)

Abstract

Let Q be a Lipschitz domain in Rn and let fL(Q). We investigate conditions under which the functional I(φ)=Q|φ|n+f(x)detφdx obeys I(φ)0 for all φW01,n(Q,Rn). We prove that there are f such that I0 holds and is strictly stronger than the best possible inequality that can be derived using Hadamard's pointwise inequality nn/2|detA||A|n alone. Almost all of the f we consider are piecewise continuous, and we specialize to the case n=2 in many occasions. We find that it is both the geometry of the `jump sets' as well as the sizes of the `jumps' themselves that determine whether I0 holds. We also outline connections to quasiconvexity at the boundary, sequential weak lower semicontinuity and to Agmon's conditions in elasticity. Theoretical results will be complemented with various numerical experiments. This is a joint work with J.~Bevan (Surrey) and J.~Valdman (Prague).

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