We define a cohomology theory for topological semigroups, with seminormed cohomology groups. Our theory can be considered as a topological version of bounded cohomology of discrete semigroups. 1. Definition of the cohomology Bounded cohomology was first defined for discrete groups by F. Trauber and then for topological spaces by M. Gromov [6]. In this paper we establish a topological bounded co...

We show that the Desch–Schappacher perturbation and the Miyadera–Voigt perturbation of an immediately norm continuous semigroup are immediately norm continuous. We also show that a perturbation theorem of C. Batty, C. Kaiser and L. Weis based on a generation theorem of A.M. Gomilko, D.-X. Feng and D.-H. Shi also preserves the immediate norm continuity of semigroups. The novelty of these results...

The following results (and one or two others like them) are proved in [3]; the continuous-parameter analogues will appear in [4] and some applications will be discussed in [5]. The proofs are based on Sz.-Nagy's group of theorems [9] which show how a discreteor continuous-parameter semigroup of contraction operators on Hilbert space can be "dilated" to a similar semigroup (actually a group) of ...

We present and explore a general method for deriving a Lie-Markov model from a finite semigroup. If the degree of the semigroup is k, the resulting model is a continuous-time Markov chain on k states and, as a consequence of the product rule in the semigroup, satisfies the property of multiplicative closure. This means that the product of any two probability substitution matrices taken from the...

in this paper we find sufficient conditions on primitive inverse topological semigroup s under which: the inversion inv : (h(s)) (h(s)) is continuous; we show that every topologically periodic countable compact primitive inverse topological semigroups with closed h-classes is topologically isomorphic to an orthogonal sum p i2= bi (gi) of topological brandt extensions bi (gi) of countably compac...

This is a contribution to the theory of sums of independent random variables at an algebraico-analytical level: Let Prob∞(R) denote the convolution semigroup of all probability measures on R with all moments finite, topologized by polynomially weighted total variation. We prove that the cumulant sequence κ = (κ : ∈ N), regarded as a function from Prob∞(R) into the additive topological group R∞ ...

1 Let (X , .) be a Banach space. In general, for a C 0-semigroup {T (t)} t≥0 on (X , .), its adjoint semigroup {T * (t)} t≥0 is no longer strongly continuous on the dual space (X * ,. which the usual semigroups in literature becomes C 0-semigroups. The main purpose of this paper is to prove that only a core can be the domain of uniqueness for a C 0-semigroup on (X * , C(X * , X)). As applicatio...

In this article, we give a unified theory for constructing boundary layer expansions for discretized transport equations with homogeneous Dirichlet boundary conditions. We exhibit a natural assumption on the discretization under which the numerical solution can be written approximately as a two-scale boundary layer expansion. In particular, this expansion yields discrete semigroup estimates tha...

We show by elementary combinatorial arguments that any non-zero homogeneous quasimorphism on a given group can be realized as the relative growth of some bi-invariant partial order on that group. Thereby we provide a link between quasimorphisms, bounded cohomology and partial orders. This yields existence results for bi-invariant partial orders, e.g. for non-elementary Gromov hyperbolic groups....

<p>A Meir-Keeler type fixed point theorem for a family of mappings is proved in Menger probabilistic metric space (Menger PM-space). We establish that completeness the equivalent to property larger class includes continuous as well discontinuous mappings. In addition it, satisfying (ϵ - δ) non-expansive established.</p>