Hadamard type inequality for quasiconvex functions in higher dimensions ✩

In this article we study a Hadamard type inequality for nonnegative evenly quasiconvex functions. The approach of our study is based on the notion of abstract convexity. We also provide an explicit calculation to evaluate the asymptotically sharp constant associated with the inequality over a unit square in the two-dimensional plane.  2002 Elsevier Science (USA). All rights reserved