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Francesco Malizia

Publications and source records attributed to Francesco Malizia.

6 recordsLinked to original sources

Quantization for Palais-Smale sequences of the Liouville functional on closed surfaces

In this paper we prove a quantization property for Palais-Smale sequences of functionals related to Liouville equations on compact surfaces. While these equations have been extensively studied over the past decades, such a quantization property had not been established so far, and has been often bypassed by the Struwe monotonicity trick. Our result, which relies on careful $L^p$ estimates to obtain gradient bounds and to perform neck analysis, allows to directly apply variational methods to obtain existence of solutions in non-resonant regimes. We also give an example of clustering of blow-up points and a stronger assumption that, on the contrary, guarantees that the blow-up points are isolated.

math.AP↗

Decreasing Weyl's energy by connected sums with locally conformally flat manifolds

We study the Weyl functional on connected sums of two four-dimensional manifolds $(M,g_M)$ and $(Z,g_Z)$, assuming $g_M$ is Bach-flat and $g_Z$ locally conformally flat. We show that if $g_M$ is neither self-dual nor anti self-dual and if $g_Z$ is of positive Yamabe class, there exists a metric $g_Y$ on $Y := M \# Z$ with Weyl energy lower than that of $g_M$ (with the trivial exception of $(Z,g_Z) = (\mathbb{S}^4, g_{\mathbb{S}^4})$). This result has a relation to a conjecture by Singer and has a perspective application to the minimization of Weyl's energy. The proof relies on a simultaneous interplay of $W_M^+, W_M^-$ and the topology of $Z$, and also covers some orbifold cases.

math.DG↗

Min-max theory and Yamabe metrics on conical four-manifolds

We prove existence of Yamabe metrics on four-manifolds possessing finitely-many conical points with $\mathbb{Z}_2$-group, using for the first time a min-max scheme in the singular setting. In our variational argument we need to deform continuously regular bubbles into singular ones, while keeping the Yamabe energy sufficiently low. For doing this, we exploit recent positive mass theorems in the conical setting and study how the mass of the conformal blow-up diverges as the blow-up point approaches the singular set.

math.DG↗

Weyl energy and connected sums of four-manifolds

Given two closed, oriented Riemannian four-manifolds $(M,g_M)$ and $(Z,g_Z)$, which are not locally conformally flat and not both self-dual or both anti-self-dual, we prove that there exists a metric $g_Y$ on the connected sum $Y\cong M\#Z$ such that the Weyl energy of $g_Y$ is strictly smaller than the sum of Weyl energies of $g_M$ and $g_Z$.

math.DG↗