Clifford and Preston (1961) showed several important characterizations of right groups. It was shown in Roy and So (1998) that, among topological semigroups, compact right simple or left cancellative semigroups are in fact right groups, and the closure of a right simple subsemigroup of a compact semigroup is always a right subgroup. In this paper, it is shown that such results can be generalize...

We generalize the concept of near weight stated in [2007, IEEE Trans. Inform. Theory 53(5), 1919–1924] in the sense that we consider maps to arbitrary wellordered semigroups instead of the nonnegative integers. This concept can be used as a tool to study AG codes based on more than one point via elementary methods only.

In this paper we introduce the notion of fuzzy  semigroup via fuzzy partial ordering and investigate some properties connected with fuzzy  semigroup. Keyword: Fuzzy  semigroup

Abstract This article proposes a resonance suppression method for flexible load servo drive system based on manipulator's pose transformation. We establish the robotic arm continuum vibration theory and transfer function estimation method. The controller consists of two parts: compensation control dynamic feedback. active feedback part is strictly positive real. At end thesis, asymptotic stabil...

In collaboration with João Araújo and others, I have been thinking about relations between permutation groups and transformation semigroups. In particular, what properties of a permutation group G on a set Ω guarantee that, if f is any non-permutation on Ω (or perhaps any non-permutation of rank k), then the transformation semigroup 〈G, f〉 has specified properties. There is far too much to summ...

We study algebraic and topological properties of topological semigroups containing a copy of the bicyclic semigroup C(p, q). We prove that each topological semigroup S with pseudocompact square contains no dense copy of C(p, q). On the other hand, we construct a consistent example of a Tychonov countably compact semigroup containing a copy of C(p, q). In this paper we study the structural prope...

In the paper we study (countably) compact and (absolutely) H-closed primitive topological inverse semigroups. We describe the structure of compact and countably compact primitive topological inverse semigroups and show that any countably compact primitive topological inverse semigroup embeds into a compact primitive topological inverse semigroup. In this paper all spaces are Hausdorff. A semigr...

We continue our investigation on the relationship between regular languages and syntactic monoid size. In this paper we confirm the conjecture on two generator transformation semigroups. We show that for every prime n ≥ 7 there exist natural numbers k and ` with n = k + ` such that the semigroup Uk,` is maximal w.r.t. its size among all (transformation) semigroups which can be generated with tw...

A transformation semigroup (ts) X = (Q,, S,) in this paper consists of a finite set of states Qx and a subsemigroup of transformations S, of PF(Q,), the monoid of all partial functions on Q, with composition as multiplication. For n > 1, ii’ denotes the transformation monoid (tm) with n states and with the n constant maps on those n states (along with the identity function) as transformations. ...

We investigate the length `(n, k) of a shortest preset distinguishing sequence (PDS) in the worst case for a k-element subset of an n-state Mealy automaton. It was mentioned by Sokolovskii [18] that this problem is closely related to the problem of finding the maximal subsemigroup diameter `(Tn) for the full transformation semigroup Tn of an n-element set. We prove that `(Tn) = 2 n exp{ √ n 2 l...