Hamiltonian cycles and subsets of discounted occupational measures

We study a certain polytope arising from embedding the Hamiltonian cycle problem in a discounted Markov decision process. The Hamiltonian cycle problem can be reduced to finding particular extreme points of a certain polytope associated with the input graph. This polytope is a subset of the space of discounted occupational measures. We characterize the feasible bases of the polytope for a general input graph $G$, and determine the expected numbers of different types of feasible bases when the underlying graph is random. We utilize these results to demonstrate that augmenting certain additional constraints to reduce the polyhedral domain can eliminate a large number of feasible bases that do not correspond to Hamiltonian cycles. Finally, we develop a random walk algorithm on the feasible bases of the reduced polytope and present some numerical results. We conclude with a conjecture on the feasible bases of the reduced polytope.Comment: revised based on referees comment

Player aggregation in the traveling inspector model

We consider a model of dynamic inspection/surveillance of a number of facilities in different geographical locations. The inspector in this process travels from one facility to another and performs an inspection at each facility he visits. His aim is to devise an inspection/ travel schedule which minimizes the losses to society (or to his employer) resulting both from undetected violations of the regulations and from the costs of the policing operation. This model is formulated as a non-cooperative, single-controller, stochastic game. The existence of stationary Nash equilibria is established as a consequence of aggregating all the inspectees into a single “aggregated inspectee”. It is shown that such player aggregation causes no loss of generality under very mild assumptions. A notion of an “optimal Nash equilibrium” for the inspector is introduced and proven to be well-defined in this context. The issue of the inspector’s power to “enforce” such an equilibrium is also discussed

On production and abatement time scales in sustainable development. Can we loosen the sustainability screw ?

In this paper we carry out a preliminary exploration of a time scales' conjecture, which postulates that "reasonable" notions of sustainability must include a suitable synchronisation of time scales of both the processes of human development and those of the natural environment. We perform our analysis within a coarse, ?ve variable, model of man-nature interactions expressed as a system of differential equations where production and human capital are coupled with both renewable and non-renewable natural resource. We demonstrate a phenomenon that we name the "sustainability screw" that describes a spiral like trajectory of the three key variables: non-renewable and renewable resources as well as the production capital. Under many plausible scenarios, this spiral tends unacceptably fast to an undesirable equilibrium. However, we also show that by adjusting the ratio of "intensity of production effort" and "intensity of abatement effort", parameters of the relative time scales of production and natural recovery processes can be altered in a manner that produces, arguably, more sustainable trajectories.sustainable optimization systems, viability, multiple time scale

Teoria narracyjności w semantyce: „wielkie” i „małe” narracje językowe a językowy obraz świata

The article incorporates the category of narrative into the scope of research of the linguistic worldview. The concept of language defined in terms of grand narrative constitutes a substantial enhancement of the theory of linguistic worldview. It introduces a category that so far has only been signalled in this current of linguistic studies as a potential option. Thus, the most important aim of my research is the projection of the category of narrative – with all its background and interdisciplinary potential (rooted in philosophy, psychology, historiosophy or cognitive sciences) – onto the realm of semantic mechanisms, which allows its application to language data analysis.Udostępnienie publikacji Wydawnictwa Uniwersytetu Łódzkiego finansowane w ramach projektu „Doskonałość naukowa kluczem do doskonałości kształcenia”. Projekt realizowany jest ze środków Europejskiego Funduszu Społecznego w ramach Programu Operacyjnego Wiedza Edukacja Rozwój; nr umowy: POWER.03.05.00-00-Z092/17-00

Here for Life: A Chapter & Stories

Four short stories and a novel chapter