21 citations · 51 across the 9 of their papers we have counts for
1 paper · 2 filters
Bernard Helffer, Mikael Persson Sundqvist
Å. Pleijel (1956) has proved that in the case of the Laplacian with Dirichlet condition, the equality in the Courant nodal theorem (Courant sharp situation) can only be true for a…