In this paper we study the relationships among the spectra of the cosets of an element of a Banach algebra in some quotient algebras. We also characterize the spectrum of any a E M (where M is an ideal of a Banach algebra with identity and moreover has an identity) in the whole algebra in terms of the spectrum of a in M.

Describing minimal generating sets of toric ideals is a well-studied and difficult problem. Neil White conjectured in 1980 that the toric ideal associated to a matroid is generated by quadrics corresponding to single element symmetric exchanges. We give a combinatorial proof of White’s conjecture for graphic matroids.

Achieving the goals in the title (and others) relies on a cardinality-wise scanning of the ideals of the poset. Specifically, the relevant numbers attached to the k + 1 elment ideals are inferred from the corresponding numbers of the k-element (order) ideals. Crucial in all of this is a compressed representation (using wildcards) of the ideal lattice. The whole scheme invites distributed comput...

Sulfolobus solfataricus and Sulfolobus islandicus contain several genes exhibiting D-arabinose-inducible expression and these systems are ideal for studying mechanisms of archaeal gene expression. At sequence level, only two highly conserved cis elements are present on the promoters: a regulatory element named ara box directing arabinose-inducible expression and the basal promoter element TATA,...

Let A be a semigroup whose only invertible element is 0. For an A-homogeneous ideal we discuss the notions of simple i-syzygies and simple minimal free resolutions of R/I. When I is a lattice ideal, the simple 0-syzygies of R/I are the binomials in I. We show that for an appropriate choice of bases every A-homogeneous minimal free resolution of R/I is simple. We introduce the gcd-complex ∆gcd(b...

The focus of this paper is to outline the experience of a European based software organization utilizing the IDEAL model, while implementing a tailored Capability Maturity Model (CMM) software process improvement program. The goal was to achieve process improvement rather than a specific CMM maturity level. In doing this, the IDEAL model was extensively researched and employed. The benefits and...

In this paper S will denote an AG-groupoid. A two-sided ideal I of S is called a right (left) pure ideal of S , if for each x in I , there is an element y in I such that ) = ( = x yx x xy . A left (right) pure ideal I is called purely prime if it is proper and if for any pure ideals 1 I and 2 I : I I I 2 1 implies I I1 or I I2 . Analogous to the construction of the pure spectrum of a semigroup ...

Multi-element arrays at both ends of a communication link (Multiple Input Multiple Output – MIMO) have the potential of increasing the throughput and/or of improving the link reliability through spatial diversity. In this paper the capability of increasing the throughput in HIPERLAN/2 (H/2) Wireless LAN (WLAN) standard by MIMO Spatial Multiplexing is investigated with both ideal and real channe...

Let K/F denote an abelian extension of number fields with associated rings of integers OK and OF . Let S denote a finite set of places of F containing the archimedean places and those which ramify in K. Assume that S contains at least one place v that splits completely in K and that |S| ≥ 2. For each ideal n ⊂ OF not divisible by a prime that ramifies in K, we denote by σn the associated Froben...

Coupling phenomena between artificial left-handed ~LH! transmission lines are explored on the basis of a transmission line approach of LH materials. A LH forward coupler in the form of an ideal lumped-element ladder network is presented and is shown to exhibit strong forward coupling that increases with decreasing of frequency. A quasi-lumped element microstrip implementation of a LH coupler is...