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Acta Mathematica Vietnamica

Sharp Constant for Poincaré-Type Inequalities in the Hyperbolic Space

icon-email Quốc Anh Ngô , Van Hoang Nguyen

Abstract

In this note, we establish a Poincaré-type inequality on the hyperbolic space Hn, namely upC(n,m,p)gmup for any uWm,p(Hn). We prove that the sharp constant C(n,m,p) for the above inequality is C(n,m,p)={(pp/(n1)2)m/2if m is even,(p/(n1))(pp/(n1)2)(m1)/2if m is odd, with p=p/(p1) and this sharp constant is never achieved in Wm,p(Hn). Our proofs rely on the symmetrization method extended to hyperbolic spaces.