Abstract

We show in this paper that the sequence {max|uk|}, where the uk are the eigenfunctions of the problem Δu+λu=0 in DRn and u=0 on D, is not bounded generally if one imposes the norm Du2p(x)dx=1, p=(1),2,3,. The same holds with the norm D|gradu|2pdx=1 when n>4p1. On the other hand, if DR2, resp. R3 the norm D|gradu|2dx=1 implies max|uk|k0, resp. max|uk|=0(1).