The aim of this paper is to give a unified comparison of non-overlapping domain decomposition methods (DDMs) for solving magnetic field problems. The methods under investigation are the Schur complement method and the Lagrange multiplier based Finite Element Tearing and Interconnecting (FETI) method, and their solvers. The performance of these methods has been investigated in detail for two-dim...

Using a new classification of 2-generator p-groups of class 2, we compute various homological functors for these groups. These functors include the nonabelian tensor square, nonabelian exterior square and the Schur multiplier. We also determine which of these groups are capable and which are unicentral.

Using the recently developed notion of a Herz-Schur multiplier C*-dynamical system we introduce weak amenability C*- and W*-dynamical systems. As special case recover Haagerup's characterisation discrete group. We also consider generalisation Fourier algebra its multipliers to crossed products.

It is known that the dimension of Schur multiplier a non-abelian nilpotent Lie algebra L n equal to 1 2 (n − 1)(n 2) + s(L) for some ≥ 0. The structure all algebras has been given ≤ 4 in several

Let D be a masa in B(H) where H is a separable Hilbert space. We find real numbers η0 < η1 < η2 < · · · < η6 so that for every bounded, normal D-bimodule map Φ on B(H), either ‖Φ‖ > η6 or ‖Φ‖ = ηk for some k ∈ {0, 1, 2, 3, 4, 5, 6}. When D is totally atomic, these maps are the idempotent Schur multipliers and we characterise those with norm ηk for 0 ≤ k ≤ 6. We also show that the Schur idempote...