Let T(X) be the full transformation semigroup on a set X, and let L(V) under composition of all linear transformations vector space V over field. For subset Y X subspace W V, consider semigroups $${\overline{T}}(X, Y) = \{f\in T(X):Yf \subseteq Y\}$$ $${\overline{L}}(V, W) L(V):Wf W\}$$ composition. We describe unit-regular elements in Y)$$ W)$$ . Using these, we determine when are unit-regular...

r is called commuting regular ring (resp. semigroup) if for each x,y $in$ r thereexists a $in$ r such that xy = yxayx. in this paper, we introduce the concept of commuting$pi$-regular rings (resp. semigroups) and study various properties of them.

In this paper, the problem of non-regular static state feedback linearization of nonlinear switched systems is considered. Using semi-tensor product, some easily verifiable sufficient conditions for non-regular feedback linearization are obtained. Then an example is presented to illustrate the non-regular linearization process.

background : life style is the ordinal and daily activities of individuals in their own lives that they accepted so, these activities affect their health status. the aim of the current study was to determine  teachers' life style in gorgan city in 2009. methods : in a cross-sectional study 336 teachers of elementary, mid and high school were recruited through random stratified sampling method. ...

We consider a polymorphic type system (System F) with recursive types for the lambda calculus with constants. We use Leivant’s notion of rank to delimit the boundaries for decidable and undecidable type inference in our system. More precisely, we show that type inference in our system is undecidable at rank k ≥ 3. Similar results are known to hold for System F without recursive types. Our undec...

We propose a unified and simple approach of capturing and recreating 3D sound fields by exploring the reciprocity principle that is satisfied between the two processes. Our approach makes the system easy to build, and practical. Using this approach, we can capture the 3D sound field by a spherical microphone array and recreate it using a spherical loudspeaker array, and ensure that the recreate...

If we construct isosceles polygon Pa k with (k − 1) sides of the same length over each side of regular polygon Pb n , with n sides, we get a new equilateral polygon P a,δ N with N = (k− 1)n sides of the same length and with different inner angles. Such polygon is called equilateral semi-regular polygon. This paper deals with metric properties of general semi-regular polygons Pa N , with given s...

A graph is semi-symmetric if it is regular and edge transitive but not vertex transitive. The 3and 4-valent semi-symmetric graphs are wellstudied. Several papers describe infinite families of such graphs and their properties. 3-valent semi-symmetric graphs have been completely classified up to 768 vertices. The goal of this project is to extend this work to 5-valent semi-symmetric graphs. In th...

This paper is the first of a two part series. In this paper, we first prove that the variety of dually quasi-De Morgan Stone semi-Heyting algebras of level 1 satisfies the strongly blended $lor$-De Morgan law introduced in cite{Sa12}. Then, using this result and the results of cite{Sa12}, we prove our main result which gives an explicit description of simple algebras(=subdirectly irreducibles) ...

We give an alternative proof of the fact that a planar function cannot exist on groups of even order. The argument involved leads us to define a class of functions which we call semi-planar. Through the introduction of an incidence structure we construct semi-biplanes using semi-planar functions. The method involved represents a new approach to constructing semi-biplanes and provides infinite c...