261 research outputs found

    Complexity of Chess Domination Problems

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    We study different domination problems of attacking and non-attacking rooks and queens on polyominoes and polycubes of all dimensions. Our main result proves that maximal domination is NP-complete for non-attacking queens and for non-attacking rooks on polycubes of dimension three and higher. We also analyse these problems for polyominoes and convex polyominoes, conjecture the complexity classes and provide a computer tool for investigation. We have also computed new values for classical queen domination problems on chessboards (square polyominoes). For our computations, we have translated the problem into an integer linear programming instance. Finally, using this computational implementation and the game engine Godot, we have developed a video game of minimal domination of queens and rooks on randomly generated polyominoes.Comment: 19 pages, 20 figures, 4 tables. Theorem 1 now for d>2, added results on approximation, fixed typos, reorganised some proof

    The European Experience: A Multi-Perspective History of Modern Europe, 1500–2000

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    The European Experience brings together the expertise of nearly a hundred historians from eight European universities to internationalise and diversify the study of modern European history, exploring a grand sweep of time from 1500 to 2000. Offering a valuable corrective to the Anglocentric narratives of previous English-language textbooks, scholars from all over Europe have pooled their knowledge on comparative themes such as identities, cultural encounters, power and citizenship, and economic development to reflect the complexity and heterogeneous nature of the European experience. Rather than another grand narrative, the international author teams offer a multifaceted and rich perspective on the history of the continent of the past 500 years. Each major theme is dissected through three chronological sub-chapters, revealing how major social, political and historical trends manifested themselves in different European settings during the early modern (1500–1800), modern (1800–1900) and contemporary period (1900–2000). This resource is of utmost relevance to today’s history students in the light of ongoing internationalisation strategies for higher education curricula, as it delivers one of the first multi-perspective and truly ‘European’ analyses of the continent’s past. Beyond the provision of historical content, this textbook equips students with the intellectual tools to interrogate prevailing accounts of European history, and enables them to seek out additional perspectives in a bid to further enrich the discipline

    Security Elites in Egypt and Jordan after the Arab Spring : A Case Study on Securocracies’ Role on National Security, Domestic Power Politics, Regional Order and Middle Eastern Alliance Making between 2011 and 2021

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    The doctoral dissertation studied changes in the balance of power, alliance making and the hegemonic struggles of security elites within a Middle Eastern regional context over a ten year reference period between 2011 and 2021. The study focused on two case study countries: Egypt and Jordan. The results were compared within a historical context to the pre-Arab Spring era. The theoretical approach combined the English School of Thought and Middle Eastern Studies with a conceptual model of securocracy developed by the author. The primary contribution of the research is the realization of the core importance of securocracy within autocratic state systems. Inside securocracies there exists rivalling groups and organisations that counterbalance each other. The study points to the fact that the power struggle between executive powers – either purely domestic one or supported by foreign involvement, is the main driver behind why case study countries were in varying degrees dragged into instability and turmoil in the aftermath of the Arab Spring. Securocracies can be divided into two main types: centralised and decentralised. The centralised model occurs when different elites groups have the same ”distance” to the ruler while having equal privileges and equal access to political power. The model predicts durability and stability of the regime (status quo). In the de-centralised model, there is an ongoing struggle amongst elite groups and “distances” to ruler are not equal, neither are the privileges. In Egypt the hegemonic struggle amongst elites took precedence over the interests and stability of the state after the Arab Spring and has continued since then. The situation at the end of 2021 is a de-centralised model where all executive powers are concentrated within President al-Sisi’s family dynasty (palace) and the leadership of military intelligence. This de-centralised type of securocracy makes Egypt’s situation fragile. Any impact from the outside, such as the Biden administration’s decision to impose additional conditions on U.S. financial military aid, could lead to a new hegemonic struggle challenging al-Sisi’s power. The securocracy’s survival strategy found in the study was the use of vertical power at all levels of the state hierarchy (” the winner takes it all”). In the situation of a power struggle, the ruler uses omni-balancing i.e., alliance making with powerful foreign states in order to gain an advantage against domestic rivals and revisionist regional states. The Egyptian example is al-Sisi’s rapprochement with Russia’s President Putin and his distancing of Egypt from its previous role of being the United States’ loyal Middle Eastern ally. The Jordanian example however, is the opposite, resulting in even closer relations with the United States since January 2021 when the two countries signed an updated Status of Forces Agreement (SOFA). The study also highlights that decisions concerning ruler succession in authoritarian states take place behind-the-scenes amongst the securocracy as it, per rule, prefers to choose a member inside its own interest group or alternatively a political figurehead that commits to protect securocracy’s privileged interests in exchange of their own power position. Within the Middle East, the recent U.S. pivot to Asia-Pacific created an opportunity for Russia to make a come-back. Russia, however, does not have the resources to compensate for the loss of U.S. financial military aid to the security elites. This in turn, and with Russia’s consent, has given space for regional state actors, particularly, the United Arab Emirates and Saudi-Arabia, to increase their influence. Gulf support to the regional clients is not free of charge: they request their clients adopt their own threat perceptions, take sides in armed conflicts and contribute to military capabilities which support the sponsors’ regional foreign and security policy goals.Väitöstutkimuksessa tarkasteltiin kymmenen vuoden ajanjaksolla voimatasapainon muutosta Lähi-idän alueellisessa valtarakenteessa, liittolaissuhteiden muutoksia sekä turvallisuuseliittien roolia maan sisäisessä valtataistelussa. Tuloksia verrattiin historiallisessa kontekstissa arabikevättä edeltävään aikaan kahdessa tapaustutkimusmaassa: Egyptissä ja Jordaniassa. Teoriaviitekehyksenä sovellettiin Englantilaisen koulukunnan ja Lähi-idän tutkimuksen teoriamalleja, sekä tutkijan kehittelemää sekurokratian konseptuaalista mallia. Tutkimuksen keskeinen tulos on havainto sekurokratian merkittävästä roolista osana autoritaarista valtiomallia. Sekurokratian sisälle on luotu useita toinen toistaan tasapainottavia ryhmittymiä. Tapaustutkimusmaiden arabikevään jälkeisen turvallisuustilanteen muutoksia selittävien tekijöiden joukossa turvallisuuseliittien valtakamppailu nousi merkittävään rooliin. Valtakamppailua käytiin eliittien kesken joko pelkästään maan sisällä tai vaihtoehtoisesti osin myös valtion ulkopuolisten voimien tukemana. Tutkimuksen perusteella sekurokratiat voidaan jakaa kahteen päätyyppiin: keskitettyyn ja hajautettuun malliin. Jos eri turvallisuuseliitti-ryhmien edut, vallankäyttö ja etäisyys vallan keskipisteeseen ovat tasapainossa puhutaan keskitetyn sekurokratian mallista, mikä ennustaa vallassa olevan regiimin pysyvyyttä ja vakautta. Jos taas sekurokratian rakenne on hajautetun mallin mukainen, sen valtakamppailu voi johtaa yhden osan pyrkimyksiin hegemonia-asemasta. Egyptin tapauksessa arabikevään jälkeinen turvallisuuseliittien valtakamppailu asetettiin maan vakauden edelle ja eliittien valtakamppailu on jatkunut tähän päivään. Tilanteessa vuoden 2021 lopussa valta on al-Sisin perhedynastialla ja sotilastiedustelun eliitillä (hajautettu malli). Hajautettu malli ei ennusta pitkäaikaista vallassa pysymistä; vahva ulkopuolinen heräte, esimerkiksi Bidenin hallinnon sotilaallisen talousavun lopettaminen voisi johtaa uuteen valtakamppailuun ja al-Sisin valta-aseman haastamiseen. Tutkimustulokset osoittavat, että sekurokratoiden selviytymisstrategiana on vallanvertikaalin käyttö valtiohallinnon eri tasoilla. Valtakamppailun tilanteessa käytetään tasapainotusstrategiaa (omni-balancing), missä alueellisia vahvoja valtioita ja suurvaltoja pyritään yhdistämään hallitsijan puolelle kilpailevia eliittiryhmittymiä tai revisionistisia ulkovaltoja vastaan. Egyptissä presidentti al-Sisin valtaannousu johti maan lähentymiseen presidentti Putinin Venäjän kanssa sekä etääntymiseen aiemmasta Yhdysvalloille uskollisen Lähi-idän liittolaisen roolista. Jordaniassa puolestaan maa on nyt entistä tiiviimmin liittoutunut Yhdysvaltojen kanssa. Esimerkkinä tästä on tammikuussa 2021 maiden kesken solmittu sotilasyhteistyötä ja jordanialaisten tukikohtien käyttöä säätelevä isäntämaatuki-sopimus. Tutkimustulosten valossa autoritaariselle vallanperimykselle tyypillistä on se, että julkisuuteen näkymättömän sisäisen valtakamppailun jälkeen uudeksi valtionpäämieheksi pyritään nostamaan sekurokratian sisältä sen oman intressiryhmän edustaja, tai vaihtoehtoisesti sekurokratian valitsema ulkopuolinen poliitikko, jonka vastuulle korporaation intressien vaaliminen lankeaa vastapalveluksena sekurokratian tuesta keulakuva-poliitikon vallassa pitämiseksi. Alueellisen turvallisuusjärjestyksen osalta tutkimuksen tulokset osoittavat sen, että Yhdysvaltojen painopisteen siirto Tyynellemerelle vii ja Aasiaan on antanut Venäjälle mahdollisuuden palauttaa vaikutusvaltaansa Lähiitään. Venäjällä ei kuitenkaan ole resursseja kompensoida Yhdysvaltojen arabivaltioiden turvallisuuseliiteille allokoimaa taloudellista tukea. Tämä on antanut tilaa alueellisten toimijoiden kuten Yhdistyneiden arabiemiirikuntien ja Saudi-Arabian vaikutusvallan kasvattamiselle - tosin Venäjän hyväksynnällä. Tuki ei myöskään tule ilmaiseksi, sillä sponsorit edellyttävät, että niille alisteisessa asemassa olevat maat omaksuvat tukijavaltioidensa uhkakuvat, sekä konfliktitilanteissa kontribuoivat sotilaallisia kyvykkyyksiä näiden valtioiden ulko- ja turvallisuuspoliittisten päämäärien saavuttamiseksi

    Improved lower bounds for Queen's Domination via an exactly-solvable relaxation

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    The Queen's Domination problem, studied for over 160 years, poses the following question: What is the least number of queens that can be arranged on a m×nm \times n chessboard so that they either attack or occupy every cell? We propose a novel relaxation of the Queen's Domination problem and show that it is exactly solvable on both square and rectangular chessboards. As a consequence, we improve on the best known lower bound for rectangular chessboards in 12.5%\approx 12.5\% of the non-trivial cases. As another consequence, we simplify and generalize the proofs for the best known lower-bounds for Queen's Domination of square n×nn \times n chessboards for n{0,1,2}mod4n \equiv \{0,1,2\} \mod 4 using an elegant idea based on a convex hull. Finally, we show some results and make some conjectures towards the goal of simplifying the long complicated proof for the best known lower-bound for square boards when n3mod4n \equiv 3 \mod 4 (and n>11n > 11). These simple-to-state conjectures may also be of independent interest.Comment: 20 pages, 7 figures For associated repo, see https://github.com/architkarandikar/queens-dominatio

    The portrayal of Emperor Kôken/Shôtoku in historical sources and belletristic works, and the circumstances which played a part in it

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    This paper examines the portrayal of the last female ruler of Nara Japan, Emperor Kôken/Shôtoku, in different sources (chronicles, graphic images, novels, and modern historiography) and the social, political, cultural and religious factors which (could) have influenced the said narrative. Having been the last woman who ascended the Imperial throne of Japan and who had actually been able to exert real authority over the court, Emperor Kôken/Shôtoku could be considered a controversial figure in the history of the Imperial House of Japan and its rulers, and had thus become an object of either criticism of praise, with some authors even holding the opinion that her politics during her two reigns are the main reason why females were excluded from the order of succession of the Imperial House of Japan. Incorporating evidence from chronicles, graphic images, novels and modern historiography, this study demonstrated that the portrayal of Emperor Kôken/Shôtoku either in a good or in a bad light depended on a set of different factors. On the one hand there are always outer elements to consider such as the political situation, the cultural or religious influences in Japan at the time of the compilation of the particular source, as well as the author’s own opinion on the Imperial House of Japan and the role of the emperor in society. On the other hand inner factors such as the fact that Kôken/Shôtoku had been the first, and so far the last, female Crown Prince in the history of the Imperial House, her reascension to the throne after dethroning her successor, her political determination and cunning, which enabled her to compete with the male courtiers and even emerge victorious from their political struggles, or her unusual preference for the Buddhist monk Dôkyô during her second reign also played a major role in the way she had been perceived by the contemporary and later authors. As a result, there are as many sources which criticise her as there are such that praise her, which contributes to the creation of the full portrait of the woman and the ruler Kôken/Shôtoku

    YEARBOOK 2019/2020. Arts Museology and Curatorship

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    Yearbook is the first collection of AMaC’s student projects developed during the first two years of the course. AMaC is a Master’s degree in Arts, Museology and Curatorship with a clear mission: to educate and train professionals with creative and research skills essential to developing successful arts and cultural heritage strategies. This broad and demanding field requires an engagement with the current debate on common goods, the identity of communities, access to heritage art, and the impact of the arts on society

    English speech practice: Tutorial for 2nd year students

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    Навчальний посібник для аудиторної та самостійної роботи студентів 2 курсу «Практика усного та писемного мовлення (англійська мова)» створений, щоб допомогти студентам – майбутнім фахівцям іноземної філології, розвинути іншомовні компетенціїTutorial for classroom and independent work of the 2nd year students "English Speech Practice" is aimed to help students - future specialists of foreign philology, develop foreign language competence

    A random Hall-Paige conjecture

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    A complete mapping of a group GG is a bijection ϕ ⁣:GG\phi\colon G\to G such that xxϕ(x)x\mapsto x\phi(x) is also bijective. Hall and Paige conjectured in 1955 that a finite group GG has a complete mapping whenever xGx\prod_{x\in G} x is the identity in the abelianization of GG. This was confirmed in 2009 by Wilcox, Evans, and Bray with a proof using the classification of finite simple groups. In this paper, we give a combinatorial proof of a far-reaching generalisation of the Hall-Paige conjecture for large groups. We show that for random-like and equal-sized subsets A,B,CA,B,C of a group GG, there exists a bijection ϕ ⁣:AB\phi\colon A\to B such that xxϕ(x)x\mapsto x\phi(x) is a bijection from AA to CC whenever aAabBb=cCc\prod_{a\in A} a \prod_{b\in B} b=\prod_{c\in C} c in the abelianization of GG. Using this result, we settle the following conjectures for sufficiently large groups. (1) We confirm in a strong form a conjecture of Snevily by characterising large subsquares of multiplication tables of finite groups that admit transversals. Previously, this characterisation was known only for abelian groups of odd order. (2) We characterise the abelian groups that can be partitioned into zero-sum sets of specific sizes, solving a problem of Tannenbaum, and confirming a conjecture of Cichacz. (3) We characterise harmonious groups, that is, groups with an ordering in which the product of each consecutive pair of elements is distinct, solving a problem of Evans. (4) We characterise the groups with which any path can be assigned a cordial labelling. In the case of abelian groups, this confirms a conjecture of Patrias and Pechenik

    HERITAGE 2022. International Conference on Vernacular Heritage: Culture, People and Sustainability

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    Vernacular architecture, tangible and intangible heritage of great importance to European and global culture, represents the response of a society culturally linked to its territory, in terms of climate and landscape. Its construction features are born from the practical experience of the inhabitants, making use of local materials, taking into consideration geographical conditions and cultural, social and constructive traditions, based on the conditions of the surrounding nature and habitat. Above all, it plays an essential role in contemporary society as it is able to teach us important principles and lessons for a respectful sustainable architecture. Vernacular Heritage: Culture, People and Sustainability will be a valuable source of information for academics and professionals in the fields of Environmental Science, Civil Engineering, Construction and Building Engineering and ArchitectureMileto, C.; Vegas López-Manzanares, F.; Cristini, V.; García Soriano, L. (2022). HERITAGE 2022. International Conference on Vernacular Heritage: Culture, People and Sustainability. Editorial Universitat Politècnica de València. https://doi.org/10.4995/HERITAGE2022.2022.15942EDITORIA
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