In a recent paper [Paths, trees and matchings under disjunctive constraints, Darmann et. al., Discr. Appl. Math., 2011] the authors add to a graph G a set of conflicts, i.e. pairs of edges of G that cannot be both in a subgraph of G. They proved hardness results on the problem of constructing minimum spanning trees and maximum matchings containing no conflicts. A forbidden transition is a parti...

Starting from a compositional operational semantics of transition P Systems we have previously defined, we face the problem of developing an axiomatization that is sound and complete with respect to some behavioural equivalence. To achieve this goal, we propose to transform the systems into a normal form with an equivalent semantics. As a first step, we introduce axioms which allow the transfor...

The radiation (reaction, Robin) boundary condition for the diffusion equation is widely used in chemical and biological applications to express reactive boundaries. The underlying trajectories of the diffusing particles are believed to be partially absorbed and partially reflected at the reactive boundary, however, the relation between the reaction constant in the Robin boundary condition and t...

We show that simultaneous rigid E-uniication, or SREU for short, is decidable and in fact EXPTIME-complete in the case of one variable. This result implies that the 8 98 fragment of intuitionistic logic with equality is decidable. Together with a previous result regarding the undecidability of the 99-fragment, we obtain a complete classiication of decidability of the prenex fragment of intuitio...

In this note we show that any k-CNF which can be refuted by a quasi-polynomial Res(polylog) refutation has a “narrow” refutation in Res (i.e., of poly-logarithmic width). Notice that while Res(polylog) is a complete proof system, this is not the case for Res if we ask for a narrow refutation. In particular is not even possible to express all CNFs with narrow clauses. But even for constant width...

Recent results have shown the interest of trees-ofBDDs [Subbarayan et al., 2007] as a suitable target language for propositional knowledge compilation from the practical side. In the present paper, the concept of tree-of-BDDs is extended to additional classes of data structures C thus leading to trees-of-C representations (ToC). We provide a number of generic results enabling one to determine t...

A new form of width restricted resolution, called \CUBI resolution" (\closure under bounded input resolution") is presented. CUBI resolution allows to eliminate the dependence on the maximal input clause length in the general lower bound for resolution from Ben-Sasson, Wigderson 99], and also the poly-time decidability problem about \k-resolution" ((Kleine B uning 93]) is bypassed (by slightly ...

We consider the scheme of indeenite constraint databases proposed by Koubarakis. This scheme can be used to represent indefinite information arising in temporal, spatial and truly spatiotemporal applications. The main technical problem that we address in this paper is the discovery of tractable classes of databases and queries in this scheme. We start with the assumption that we have a class of...

Convex solutions to the power-of-mean curvature flow, conformally invariant inequalities and regularity results in some applications of optimal transportation Shibing Chen Doctor of Philosophy Graduate Department of Mathematics University of Toronto 2012 In this thesis we study three different problems: convex ancient solutions to the power-ofmean curvature flow; Sharp inequalities; regularity ...

The problem of assessing occupational exposure using the mean of a lognormal distribution is addressed. The novel concepts of generalized p-values and generalized confidence intervals are applied for testing hypotheses and computing confidence intervals for a lognormal mean. The proposed methods perform well, they are applicable to small sample sizes, and they are easy to implement. Power studi...