The default nonmonotonic reasoning was formalised by a class of logical systems: default logics (classical, justified, constrained, rational), based on the same syntax which utilises nonmonotonic inference rules: defaults, but with different semantics for the defaults. In this paper we introduce a uniform semantic characterisation for the constrained and rational extensions of a default theory....

We establish a maximin characterisation of the linear escape rate of the orbits of a non-expansive mapping on a complete (hemi-)metric space, under a mild form of Busemann’s non-positive curvature condition (we require a distinguished family of geodesics with a common origin to satisfy a convexity inequality). This characterisation, which involves horofunctions, generalises the Collatz-Wielandt...

A celebrated contribution of Bellantoni and Cook was a function algebra to capture FPTIME. This algebra uses recursion on notation. Later, Oitavem showed that including primitive recursion, an algebra is obtained which captures FPSPACE. The main results of this paper concern variants of the latter algebra. First, we show that iteration can replace primitive recursion. Then, we consider the resu...

An element A of the n× n copositive cone C is called irreducible with respect to the nonnegative cone N if it cannot be written as a nontrivial sum A = C + N of a copositive matrix C and an elementwise nonnegative matrix N . This property was studied by Baumert [2] who gave a characterisation of irreducible matrices. We demonstrate here that Baumert’s characterisation is incorrect and give a co...

In formal language theory, many families of languages are defined using either grammars or finite acceptors. For instance, context-sensitive languages are the languages generated by growing grammars, or equivalently those accepted by Turing machines whose work tape’s size is proportional to that of their input. A few years ago, a new characterisation of context-sensitive languages as the sets o...

The topological containment problem is known to be polynomial-time solvable for any fixed pattern graph H , but good characterisations have been found for only a handful of non-trivial pattern graphs. The complete graph on five vertices, K5, is one pattern graph for which a characterisation has not been found. The discovery of such a characterisation would be of particular interest, due to the ...

Chemical analysis for the characterisation of micro-organisms is rapidly evolving, after the recent advent of new ionisation methods in mass spectrometry (MS): electrospray (ES) and matrix-assisted laser desorption/ionisation (MALDI). These methods allow quick characterisation of micro-organisms, either directly or after minimum sample preparation. This review provides a brief introduction to E...

We present an approach to the automatic construction of decision procedures , via a detailed example in propositional logic. The approach adapts the methods of proof-planning, and particularly the technique of rippling BSvH + 93], to a new domain, that of meta-theoretic procedures. This approach starts by providing an alternative characterisation of validity; the proofs of the correctness of th...

Measurement of a tissue-specific electrical resistance may offer a discriminatory metric for evaluation of tissue health during cancer surgery. With a move toward minimally-invasive procedures, applicable contact sensing modalities must be scalable, fast and robust. A passive resistance characterisation method utilising a biogalvanic cell as an intrinsic power source has been proposed as a pote...

introduction: organic fertilizers are beneficial to maintain and improve structure of the soil nutrients; however, in case of presence of pathogenic microbial agents and pathogens inside them, it will result in health problems and disease transmission. therefore, present study aimed to determine microbial quality of produced vermicomposts in yazd city. methods: this study was a descriptive-anal...