We propose a class of higher-derivative gravities that can be viewed as the Gauss-Bonnet extension Starobinsky model. The theory admits Minkowski spacetime vacuum whose linear spectrum consists graviton and massive scalar mode. In addition to usual Schwarzschild black hole, we use numerical analysis establish in some suitable mass range, new holes carrying hair emerge. hole serves "wall" separa...

In a model of spontaneous scalarization neutron stars proposed by Damour and Esposito-Farese, general relativistic branch becomes unstable to trigger tachyonic growth scalar field $\ensuremath{\phi}$ toward scalarized branch. Applying this scenario cosmology, there is fatal instability during inflation matter dominance being incompatible with solar-system constraints on today's value ${\ensurem...

Black holes in scalar-Gauss-Bonnet gravity are prone to scalarization, that is a spontaneous development of scalar hair for strong enough spacetime curvature while the weak field regime theory coincides with general relativity. Since large associated smaller black hole masses, merging can lead dynamical descalarization. This release newly formed case its mass above scalarization threshold. Depe...

The authors provide a model for dynamical scalarization, beyond the adiabatic approximation, using effective field theory techniques, demonstrating that inclusion of post-adiabatic corrections is crucial. agnostic, i.e., independent specific gravity and can therefore be used even alternative theories.

In this paper we introduce some contractive conditions of Meir–Keeler type for two mappings, called f -MK -pair mappings and f -CJM-pair (from Ciric, Jachymski, and Matkowski) mappings, in the framework of regular cone metric spaces and we prove theorems which guarantee the existence and uniqueness of common fixed points. We give also a fixed point result for a multivalued mapping that satisfie...

In the presentwork, usingMinkowski functionals in topological vector spaces, we establish the equivalence between some fixed point results in metric and in (topological vector space) cone metric spaces. Thus, a lot of results in the cone metric setting can be directly obtained from their metric counterparts. In particular, a common fixed point theorem for f -quasicontractions is obtained. Our a...

In vector optimization with a variable ordering structure the partial ordering defined by a convex cone is replaced by a whole family of convex cones, one associated with each element of the space. In recent publications it was started to develop a comprehensive theory for these vector optimization problems. Thereby also notions of proper efficiency were generalized to variable ordering structu...

Given a closed convex cone P with nonempty interior in a locally convex vector space, and a set A ⊂ Y , we provide various equivalences to the implication A ∩ (−int P ) = ∅ =⇒ co(A) ∩ (−int P ) = ∅, among them, to the pointedness of cone(A + int P ). This allows us to establish an optimal alternative theorem, suitable for vector optimization problems. In addition, we characterize the two-dimens...