Spectre des Laplaciens de Lichnerowicz sur les sphères et les projectifs réels

In this paper, we compute the spectrum of the Lichnerowicz laplacian on the symmetric forms of degree 2 on the sphere $S^n$ and the real projective space ${\mathbb R} P^n$. This is obtained by generalizing to forms the calculations of the spectrum of the laplacian on fonctions done via restriction of harmonic polynomials on euclidean space.