Algorithms for Highly Symmetric Linear and Integer Programs

This paper deals with exploiting symmetry for solving linear and integer programming problems. Basic properties of linear representations of finite groups can be used to reduce symmetric linear programming to solving linear programs of lower dimension. Combining this approach with knowledge of the geometry of feasible integer solutions yields an algorithm for solving highly symmetric integer linear programs which only takes time which is linear in the number of constraints and quadratic in the dimension.Comment: 21 pages, 1 figure; some references and further comments added, title slightly change

The Development of an Information Society and Electronic Commerce in the European Union in the Context of Selected Documents of the EU and International Organisations

In this article, the author presents selected documents on electronic commerce published by the United Nations Commission on International Trade Law, the World Trade Organization, the Organisation for Economic Cooperation and Development, the International Chamber of Commerce and the European Union since 1994.W niniejszym artykule autor prezentuje wybrane dokumenty dotyczące handlu elektronicznego opublikowane przez Komisję ONZ ds. Prawa Handlu Międzynarodowego, Światową Organizację Handlu OECD, Międzynarodową Izbę Handlu oraz Unię Europejską od roku 1994

The comfort zone: Reflection on a taken-for-granted model

Reference to the comfort zone model is widespread within outdoor adventure education. It is based on the belief that when placed in a stressful situation people will respond by overcoming their hesitancy and grow. This model is often presented to students prior to activities with a perceived sense of risk and challenge which arouses strong emotional and physical responses to novel tasks (e.g., a ropes course). Students are encouraged to ‘stretch themselves’, to move outside their comfort zone and expand their preconceived limits and by inference learn. This article briefly explores the theories that underpin the comfort zone model and suggests that it is time to rethink how it is used

A Note on the Sticky Matroid Conjecture

A matroid is sticky if any two of its extensions by disjoint sets can be glued together along the common restriction (that is, they have an amalgam). The sticky matroid conjecture asserts that a matroid is sticky if and only if it is modular. Poljak and Turzik proved that no rank-3 matroid having two disjoint lines is sticky. We show that, for r at least 3, no rank-r matroid having two disjoint hyperplanes is sticky. These and earlier results show that the sticky matroid conjecture for finite matroids would follow from a positive resolution of the rank-4 case of a conjecture of Kantor.Comment: 5 pages, 2 figure

Millenium Development Goals/UN and Sustainable Development Goals/UN as Instruments for Realising Sustainable Development Concept in the Global Economy

This article presents the results of analysis and evaluation of the main effects of the implementation of the eight UN Millennium Development Goals, in force until 2015, and to demonstrate differences between and prospects for implementation of the new 2030 Agenda for Sustainable Development, covering 17 Sustainable Development Goals (SDGs) established by the international community for the next 15 years. The article also presents the contribution of the European Union as a key global donor of development aid for developing countries, especially for the least developed countries (LDCs), as well as plans for Poland’s implementation of the Post-2015 Agenda SDGs