We study how conserved quantities such as angular momentum and center of mass evolve with respect to the retarded time at null infinity, which is described in terms of a Bondi-Sachs coordinate system. These evolution formulae complement the classical Bondi mass loss formula for gravitational radiation. They are further expressed in terms of the potentials of the shear and news tensors. The consequences that follow from these formulae are (1) Supertranslation invariance of the fluxes of the CWY conserved quantities. (2) A conservation law of angular momentum \`a la Christodoulou. (3) A duality paradigm for null infinity. In particular, the supertranslation invariance distinguishes the CWY angular momentum and center of mass from the classical definitions.
In this paper, we discuss the Weyl problem in warped product spaces. We apply the method of continuity and prove the openness
of the Weyl problem. A counterexample is constructed to show that the isometric embedding of the sphere with canonical metric
is not unique up to an isometry if the ambient warped product space is not a space form. Then, we study the rigidity of the
standard sphere if we fix its geometric center in the ambient space. Finally, we discuss a Shi-Tam type of inequality for the
Schwarzschild manifold as an application of our findings.
A variational formula for the Lutwak affine surface areas j of convex bodies in Rn is
established when 1 ≤ j ≤ n − 1. By using introduced new ellipsoids associated with
projection functions of convex bodies, we prove a sharp isoperimetric inequality for j ,
which opens up a new passage to attack the longstanding Lutwak conjecture in convex
Existence and uniqueness of the solution to the Lp Minkowski
problem for the electrostatic p-capacity are proved when p > 1
and 1 < p < n. These results are nonlinear extensions of the very
recent solution to the Lp Minkowski problem for p-capacity when
p = 1 and 1 < p < n by Colesanti et al. and Akman et al., and
the classical solution to the Minkowski problem for electrostatic
capacity when p = 1 and p = 2 by Jerison.
We study the local curvature estimates of long-time solutions to the normalized Kähler-Ricci flow on compact Kähler manifolds with semi-ample canonical line bundle. Using these estimates, we prove that on such a manifold, the set of singular fibers of the semi-ample fibration on which the Riemann curvature blows up at time-infinity is independent of the choice of the initial Kähler metric. Moreover, when a regular fiber of the semi-ample fibration is not a finite quotient of a torus, we determine the exact curvature blow-up rate of the Kähler-Ricci flow near the regular fiber.
We further develop the asymptotic analytic approach to the study of scattering diagrams. We do so by analyzing the asymptotic behavior of Maurer--Cartan elements of a differential graded Lie algebra constructed from a (not-necessarily tropical) monoid-graded Lie algebra. In this framework, we give alternative differential geometric proofs of the consistent completion of scattering diagrams, originally proved by Kontsevich--Soibelman, Gross--Siebert and Bridgeland. We also give a geometric interpretation of theta functions and their wall-crossing. In the tropical setting, we interpret Maurer--Cartan elements, and therefore consistent scattering diagrams, in terms of the refined counting of tropical disks. We also describe theta functions, in both their tropical and Hall algebraic settings, in terms of distinguished flat sections of the Maurer--Cartan-deformed differential. In particular, this allows us to give a combinatorial description of Hall algebra theta functions for acyclic quivers with non-degenerate skew-symmetrized Euler forms.
Deformation quantization and geometric quantization on K\"ahler manifolds give the mathematical description of the algebra of quantum observables and the Hilbert spaces respectively, where the later forms a representation of quantum observables asymptotically via Toeplitz operators. When there is a Hamiltonian $G$-action on a K\"ahler manifold, there are associated symmetries on both the quantum algebra and representation aspects. We show that in nice cases of coadjoint orbits and K\"ahler-Einstein manifolds, these symmetries are strictly compatible (not only asymptotically).