  Let P be an hyperplane in R^N, and denote by dH the Hausdorff distance. We
show that for all positive radius r < 1 there is an epsilon > 0, such that if K
is a Reifenberg-flat set in B(0; 1), a ball in R^N, that contains the origin,
with d_H(K; P) <epsilon, and if u is an energy minimizing function in B(0; 1)\K
with restricted values on @B(0; 1)\K, then the normalized energy of u in B(0;
r)\K is bounded by the normalized energy of u in B(0; 1)\K. We also prove the
same result in R^3 when K is a epsilon-minimal set, that is a generalization of
Reifenberg-flat sets with minimal cones of type Y and T. Moreover, the result
is still true for a further generalization of sets called (eps; eps_0)-minimal.
This article is a preliminary study for a forthcoming paper where a regularity
result for the singular set of the Mumford-Shah functional close to minimal
cones in R^3 is proved by the same author.
