18 citations · 90 across the 16 of their papers we have counts for
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math.DG2020
One can't hear orientability of surfaces
Pierre Bérard, David L. Webb
The main result of this paper is that one cannot hear orientability of a surface with boundary. More precisely, we construct two isospectral flat surfaces with boundary with the sa…
math.GT2020★ 2 cited
An Euler-type formula for partitions of the Möbius strip
Pierre Bérard, Bernard Helffer
The purpose of this note is to prove an Euler-type formula for partitions of the Möbius strip. This formula was introduced in our joint paper with R.~Kiwan, "Courant-sharp property…
math.SP2020★ 6 cited
Courant-sharp property for Dirichlet eigenfunctions on the Möbius strip
Pierre Bérard, Bernard Helffer, Rola Kiwan
The question of determining for which eigenvalues there exists an eigenfunction which has the same number of nodal domains as the label of the associated eigenvalue (Courant-sharp…