Paolo Mastrolia

Maximum principles and geometric applications

A crash course in Riemannian geometry.- The Omori-Yau maximum principle.- New forms of the maximum principle.- Sufficient conditions for the validity of the weak maximum principle.- Miscellany results for submanifolds.- Applications to hypersurfaces.- Hypersurfaces in warped products.- Applications to Ricci Solitons.- Spacelike hypersurfaces in Lorentzian spacetimes.

SOME GEOMETRIC ANALYSIS ON GENERIC RICCI SOLITONS

We study the geometry of complete generic Ricci solitons with the aid of some geometric-analytical tools extending techniques of the usual Riemannian setting.

Yamabe-type equations on complete, noncompact manifolds

Introduction.- 1 Some Riemannian Geometry.- 2 Pointwise conformal metrics.- 3 General nonexistence results.- 4 A priori estimates.- 5 Uniqueness.- 6 Existence.- 7 Some special cases.- References.- Index.

Conformal Ricci solitons and related integrability conditions

Abstract We introduce, in the Riemannian setting, the notion of conformal Ricci soliton, which includes as particular cases Einstein manifolds, conformal Einstein manifolds and (generic and gradient) Ricci solitons. We provide necessary integrability conditions for the existence of these structures that also recover, in the corresponding contexts, those already known in the literature for conformally Einstein manifolds and for gradient Ricci solitons. A crucial tool in our analysis is the construction of (0, 3)-tensors related to the geometric structures, that in the special case of gradient Ricci solitons become the celebrated tensor D recently introduced by Cao and Chen. We derive commutation rules for covariant derivatives (of functions and tensors) and of transformation laws of some geometric objects under a conformal change of the underlying metric.

Some triviality results for quasi-Einstein manifolds and Einstein warped products

In this paper we prove a number of triviality results for Einstein warped products and quasi-Einstein manifolds using different techniques and under assumptions of various nature. In particular we obtain and exploit gradient estimates for solutions of weighted Poisson-type equations and adaptations to the weighted setting of some Liouville-type theorems.

Classification of expanding and steady Ricci solitons with integral curvature decay

In this paper we prove new classification results for nonnegatively curved gradient expanding and steady Ricci solitons in dimension three and above, under suitable integral assumptions on the scalar curvature of the underlying Riemannian manifold. In particular we show that the only complete expanding solitons with nonnegative sectional curvature and integrable scalar curvature are quotients of the Gaussian soliton, while in the steady case we prove rigidity results under sharp integral scalar curvature decay. As a corollary, we obtain that the only three dimensional steady solitons with less than quadratic volume growth are quotients of

A variational characterization of flat spaces in dimension three

\mathbb{R}\times\Sigma^{2}

On the relation between conformally invariant operators and some geometric tensors

, where

A Crash Course in Riemannian Geometry

\Sigma^{2}

Miscellany Results for Submanifolds

is Hamiltons cigar.