Global symplectic coordinates on gradient Kaehler-Ricci solitons

A classical result of D. McDuff asserts that a simply-connected complete Kaehler manifold $(M,g,\omega)$ with non positive sectional curvature admits global symplectic coordinates through a symplectomorphism $\Psi: M\rightarrow R^{2n}$ (where $n$ is the complex dimension of $M$), satisfying the following property (proved by E. Ciriza): the image $\Psi (T)$ of any complex totally geodesic submanifold $T\subset M$ through the point $p$ such that $\Psi(p)=0$, is a complex linear subspace of $C^n \simeq R^{2n}$. The aim of this paper is to exhibit, for all positive integers $n$, examples of $n$-dimensional complete Kaehler manifolds with non-negative sectional curvature globally symplectomorphic to $R^{2n}$ through a symplectomorphism satisfying Ciriza's property.Comment: 8 page

Finite TYCZ expansions and cscK metrics

Let $(M, g)$ be a Kaehler manifold whose associated Kaehler form $\omega$ is integral and let $(L, h)\rightarrow (M, \omega)$ be a quantization hermitian line bundle. In this paper we study those Kaehler manifolds $(M, g)$ admitting a finite TYCZ expansion. We show that if the TYCZ expansion is finite then $T_{mg}$ is indeed a polynomial in $m$ of degree $n$, $n=dim M$, and the log-term of the Szeg\"{o} kernel of the disc bundle $D\subset L^*$ vanishes (where $L^*$ is the dual bundle of $L$). Moreover, we provide a complete classification of the Kaehler manifolds admitting finite TYCZ expansion either when $M$ is a complex curve or when $M$ is a complex surface with a cscK metric which admits a radial Kaehler potential

Symplectic duality between complex domains

In this paper after extending the denition of symplectic duality (given in [3] for bounded symmetric domains ) to arbitrary complex domains of Cn centered at the origin we generalize some of the results proved in [3] and [4] to those domain

Effect of stitching on the static and fatigue properties of fibre-dominated and matrix-dominated composite laminates

The paper reports the results of an experimental investigation into the effect of stitching on the static and fatigue response of fibre-dominated and matrix-dominated laminates. The tests were conducted on stitched carbon/epoxy laminates with quasi-isotropic ([0/±45/90]s) or angle-ply ([+302/− 302]s, [+452/− 452]s, [+602/− 602]s) layups. The analyses show that stitching significantly reduces both the static and the fatigue strength of fibredominated [0/±45/90]s laminates, owing to the presence of localized fibre damage introduced during the stitching process. On the other hand, stitching does not affect the fatigue response of [+602/− 602]s laminates but significantly improves the fatigue strength of [+302/− 302]s and [+452/− 452]s laminates. The effectiveness of stitching on the fatigue performance of the angle-ply layups was found to be directly related to the specific damage mechanisms preceding the ultimate failure, which are controlled by edge delaminations in [+302/− 302]s and [+452/− 452]s and transverse matrix cracking in [+602/− 602]s laminates

Kahler–Ricci Solitons Induced by Infinite-Dimensional Complex Space Forms

We exhibit families of nontrivial (i.e., not Kähler–Einstein) radial Kähler– Ricci solitons (KRS), both complete and not complete, which can be Kähler immersed into infinite-dimensional complex space forms. This shows that the triviality of a KRS induced by a finite-dimensional complex space form proved by Loi and Mossa (Proc. Amer. Math. Soc. 149:11 (2020), 4931–4941) does not hold when the ambient space is allowed to be infinite-dimensional. Moreover, we show that the radial potential of a radial KRS induced by a nonelliptic complex space form is necessarily defined at the origin

A characterization of complex space forms via Laplace operators

Inspired by the work of Lu and Tian (Duke Math J 125(2):351–387, 2004), in this paper we address the problem of studying those Kähler manifolds satisfying the Δ -property, i.e. such that on a neighborhood of each of its points the kth power of the Kähler Laplacian is a polynomial function of the complex Euclidean Laplacian, for all positive integer k (see below for its definition). We prove two results: (1) if a Kähler manifold satisfies the Δ -property then its curvature tensor is parallel; (2) if an Hermitian symmetric space of classical type satisfies the Δ -property then it is a complex space form (namely it has constant holomorphic sectional curvature). In view of these results we believe that if a Kähler manifold satisfies the Δ -property then it is a complex space form

Extremal Kähler Metrics Induced by Finite or Infinite-Dimensional Complex Space Forms

In this paper, we address the problem of studying those complex manifolds M equipped with extremal metrics g induced by finite or infinite-dimensional complex space forms. We prove that when g is assumed to be radial and the ambient space is finite-dimensional, then (M, g) is itself a complex space form. We extend this result to the infinite-dimensional setting by imposing the strongest assumption that the metric g has constant scalar curvature and is well behaved (see Definition 1 in the Introduction). Finally, we analyze the radial Kähler–Einstein metrics induced by infinite-dimensional elliptic complex space forms and we show that if such a metric is assumed to satisfy a stability condition then it is forced to have constant nonpositive holomorphic sectional curvature

On the third coefficient of TYZ expansion for radial scalar flat metrics

We classify radial scalar flat metrics with constant third coefficient of its TYZ expansion. As a byproduct of our analysis we provide a characterization of Simanca's scalar flat metric

On canonical radial Kahler metrics

We prove that a radial Kahler metric g is Kahler-Einstein if and only if one of the following conditions is satisfied: 1. g is extremal and it is associated to a Kahler-Ricci soliton; 2. two different generalized scalar curvatures of g are constant; 3. g is extremal (not cscK) and one of its generalized scalar curvature is constant