In this paper, we obtain a forbidden minor characterization of a cographic matroid M for which the splitting matroid Mx,y is graphic for every pair x, y of elements of M .

A semigroup is amiable if there is exactly one idempotent in each R⇤-class and in each L⇤-class. A semigroup is adequate if it is amiable and if its idempotents commute. We characterize adequate semigroups by showing that they are precisely those amiable semigroups which do not contain isomorphic copies of two particular nonadequate semigroups as subsemigroups.

We introduce the s-Plex Editing problem generalizing the well-studied Cluster Editing problem, both being NP-hard and both being motivated by graph-based data clustering. Instead of transforming a given graph by a minimum number of edge modifications into a disjoint union of cliques (Cluster Editing), the task in the case of s-Plex Editing is now to transform a graph into a disjoint union of so...

We introduce the s-Plex Cluster Editing problem as a generalization of the wellstudied Cluster Editing problem, both being NP-hard and both being motivated by graph-based data clustering. Instead of transforming a given graph by a minimum number of edge modifications into a disjoint union of cliques (this is Cluster Editing), the task in the case of s-Plex Cluster Editing is to transform a grap...

The study describes the synthesis and characterization of zinc(II) minoxidil nanocomposite (1). The reaction between zinc(II) acetate, minoxidil, {C9H15N5O=minoxidil=(2,4-diamino-6-piperidine-1-yl) pyrimidine N-oxide)} as a ligand and KI as bridging agent, in methanol at 60°C leads to the formation of nano-sized Zn(II) minoxidil nanocomposite, 1. Characterization of (1) was carried out by eleme...

We report the isolation, characterization, and development of a robust genetic system for a halophilic, Fe(II)-oxidizing bacterium isolated from a vertical borehole originating 714 m below the surface located in the Soudan Iron Mine in northern Minnesota, USA. Sequence analysis of the 16S rRNA gene places the isolate in the genus Marinobacter of the Gammaproteobacteria. The genome of the isolat...

In this paper we study the chromatic number for graphs with forbidden induced subgraphs. We focus our interest on graph classes (de2ned in terms of forbidden induced subgraphs) for which the question of 3-colourability can be decided in polynomial time and, if so, a proper 3-colouring can be determined also in polynomial time. Note that the 3-colourability decision problem is a well-known NP-co...

Many factors influence the near-field visualization of plasmonic structures that are based on perforated elliptical slits. Here, characterization errors are experimentally analyzed in detail from both fabrication and measurement points of view. Some issues such as geometrical parameter, probe-sample surface interaction, misalignment, stigmation, and internal stress, have influence on the final ...

For various graph-theoretic properties P that impose upper bounds on the minimum degree or the size of a neighbourhood set, we characterize the class %(P’) (%((P’)) of graphs G such that G and all its subgraphs (subcontractions) have property P. For example, if P is “6 <xn” (6 = minimum degree, n = number of vertices, 0 <X < 1) then S(P’) = F(K,+,), the class of graphs that do not have K,,, as ...

We study which infinite posets have simple cofinal subsets such as chains, or decompose canonically into such subsets. The posets of countable cofinality admitting such a decomposition are characterized by a forbidden substructure; the corresponding problem for uncountable cofinality remains open.