“…When the manifold (M, g) is Einstein, the Paneitz Since 1990 many results have been established for precise functions a, h and f. D.E. Edmunds, D. Fortunato, E. Jannelli ( [8]) proved for n ≥ 8 that if λ ∈ (0, λ 1 ), with λ 1 is the first eigenvalue of ∆ 2 In 1995, R. Van der Vorst ( [12]) obtained the same results as D.E. Edmunds, D. Fortunato, E. Jannelli.…”