We consider complex Fenchel–Nielsen coordinates on the quasi-Fuchsian space of punctured tori. These coordinates arise from a generalisation of Kra’s plumbing construction and are related to earthquakes on Teichmüller space. They also allow us to interpolate between two coordinate systems on Teichmüller space, namely the classical Fuchsian space with Fenchel–Nielsen coordinates and the Maskit e...

The definition of quasi-local mass for a bounded space-like region Ω in space-time is essential in several major unsettled problems in general relativity. The quasi-local mass is expected to be a type of flux integral on the boundary two-surface Σ = ∂Ω and should be independent of whichever space-like region Σ bounds. An important idea which is related to the Hamiltonian formulation of general ...

We introduce a new family of Space-Time Trellis Codes which extends the powerful characteristics of SuperOrthogonal Space-Time Trellis Codes to four transmit antennas. We consider a family of quasi-orthogonal space-time block codes as building blocks in our new trellis codes. These codes combine set-partitioning and a super set of quasi-orthogonal space-time block codes in a systematic way to p...

1. Introduction. Let S be an oriented closed surface of genus g > 1. A projec-tive structure on S is a maximal system of local coordinates modeled on the Riemann sphere C, whose transition functions are Möbius transformations. For a given pro-jective structure on S, we have a pair (f, ρ) of a local homeomorphism f from the universal cover S of S to C, called a developing map, and a group homomo...

BRANKO CURGUS and BRANKO NAJMAN Deenitizable operators in Krein spaces have spectral properties similar to those of selfadjoint operators in Hilbert spaces. A suucient condition for deenitizability of a selfadjoint operator A with a nonempty resolvent set (A) in a Krein space (H; j ]) is the niteness of the number of negative squares of the form Axjy] (see 10, p. 11]). In this note we consider ...

We show that any finitely generated group quasi-isometric to complex hyperbolic space is a finite extension of a properly discontinuous, cocompact subgroup of the isometry group.