Rigidity of complete non-compact generalized m-quasi-Einstein manifolds
We study complete non compact gradient generalized m quasi Einstein manifolds with constant scalar curvature R <= 0, soliton function lambda > 0, and m > 1, where the coefficient mu = 1/m is constant. We introduce the weighted function v and prove it is subharmonic. This leads to four rigidity results, showing that the hypotheses are mutually inconsistent; consequently, no complete non compact gradient generalized m quasi Einstein manifold exists under the stated assumptions. We first show by a concrete example that if mu is allowed to be nonconstant, the rigidity conclusions fail even when all other hypotheses are satisfied. Therefore the constant mu condition is essential.