Results 31 to 40 of about 290 (118)
Four‐Dimensional pp‐Wave Lie Groups and Harmonic Curvature
ABSTRACT We determine all four‐dimensional Lie groups which have harmonic curvature. In parallel, a description of four‐dimensional pp‐wave Lie groups is obtained.
E. García‐Río +2 more
wiley +1 more source
An immersion theorem for Vaisman manifolds
A locally conformally Kähler (LCK) manifold is a complex manifold admitting a Kähler covering , with monodromy acting on by Kähler homotheties. A compact LCK manifold is Vaisman if it admits a holomorphic flow acting by non-trivial homotheties on .
Verbitsky, M., Ornea, L.
core +1 more source
Proper 3‐realizability and second cohomology of groups on two generators of finite order
Abstract Given an (infinite) finitely generated group G$G$, its first cohomology group H1(G;ZG)$H^1(G;{\mathbb {Z}}G)$ is free abelian and “counts” the number of ends of G$G$ which equals 1+rank(H1(G;ZG))$1 + rank (H^1(G;{\mathbb {Z}}G))$. The question whether or not for every finitely presented group G$G$ its second cohomology group H2(G;ZG)$H^2(G ...
Francisco F. Lasheras, R. Roy
wiley +1 more source
Scaling and conformal symmetries for plane gravitational waves
The isometries of an exact plane gravitational wave are symmetries for both massive and massless particles. Their conformal extensions are in fact chrono-projective transformations introduced earlier by Duval et al are symmetries for massless particles ...
Horvathy, Peter +8 more
core +1 more source
Locally conformally Kähler manifolds admitting a holomorphic conformal flow [PDF]
A manifold M is locally conformally Kähler (LCK) if it admits a Kähler covering ˜M with monodromy acting by holomorphic homotheties. Let M be an LCK manifold admitting a holomorphic conformal flow of diffeomorphisms, lifted to a non-isometric homothetic ...
Verbitsky, Misha, Ornea, Liviu
core +1 more source
Extremal rate of convergence in continuous dynamics
Abstract This paper deals with semigroups of holomorphic self‐maps of the upper half‐plane that exhibit an extremal (i.e., the slowest possible) rate of convergence to their Denjoy–Wolff point. The main novelty lies in the parabolic case of zero hyperbolic step.
Francisco J. Cruz‐Zamorano +1 more
wiley +1 more source
New results on embeddings of self‐similar sets via renormalization
Abstract For self‐similar sets X,Y⊆R$X,Y\subseteq \mathbb {R}$, we obtain new results toward the affine embeddings conjecture of Feng–Huang–Rao (2014), and the equivalent weak intersections conjecture. We show that the conjecture holds when the defining maps of X,Y$X,Y$ have algebraic contraction ratios, and also for arbitrary Y$Y$ when the maps ...
Amir Algom, Michael Hochman, Meng Wu
wiley +1 more source
The Geometric Transformations in Space: Isometries
This study proposes the characterization of geometric transformations in space, with particular reference to Isometries and to Homotheties, with simple demonstrations of Euclidean type.
Ferdinando Casolaro +2 more
doaj
Cohomogeneity‐one solitons in Laplacian flow: Local, smoothly‐closing and steady solitons
Abstract We initiate a systematic study of cohomogeneity‐one solitons in Bryant's Laplacian flow of closed G2$\text{G}_2$‐structures on a 7‐manifold, motivated by the problem of understanding finite‐time singularities of that flow. Here, we focus on solitons with symmetry groups Sp(2)${\rm Sp}(2)$ and SU(3)${\rm SU}(3)$; in both cases, we prove the ...
Mark Haskins, Johannes Nordström
wiley +1 more source
Kuramoto Model on Sierpinski Gasket I: Harmonic Maps
ABSTRACT Motivated by the study of attractors in the Kuramoto model (KM) on graphs, approximating the Sierpinski gasket (SG), we revisit the problem of harmonic maps (HMs) from SG to the circle, first considered by Strichartz. We provide a geometric proof of Strichartz's theorem, which states that for a prescribed degree and suitable boundary ...
Georgi S. Medvedev, Matthew S. Mizuhara
wiley +1 more source

