Everywhere regularity for a class of vectorial functionals under subquadratic general growth conditions

We consider the integral functional of the calculus of variations Ω f (Du)dx, where f :RnN →R satisfies f (z) = g(|z|) and g is an N-function with subquadratic p–q growth. We prove that minimizers u:Ω ⊂ Rn →RN of such a functional are locally Lipschitz continuous, provided g verifies some additional conditions.  2003 Elsevier Inc. All rights reserved