The Art Gallery Problem is ∃ℝ-complete

The Art Gallery Problem (AGP) is a classic problem in computational geometry, introduced in 1973 by Victor Klee. Given a simple polygon 풫 and an integer k , the goal is to decide if there exists a set G of k guards within 풫 such that every point p ∈ 풫 is seen by at least one guard g ∈ G . Each guard corresponds to a point in the polygon 풫, and we say that a guard g sees a point p if the line segment pg is contained in 풫. We prove that the AGP is ∃ ℝ-complete, implying that (1) any system of polynomial equations over the real numbers can be encoded as an instance of the AGP, and (2) the AGP is not in the complexity class NP unless NP = ∃ ℝ. As a corollary of our construction, we prove that for any real algebraic number α, there is an instance of the AGP where one of the coordinates of the guards equals α in any guard set of minimum cardinality. That rules out many natural geometric approaches to the problem, as it shows that any approach based on constructing a finite set of candidate points for placing guards has to include points with coordinates being roots of polynomials with arbitrary degree. As an illustration of our techniques, we show that for every compact semi-algebraic set S ⊆ [0, 1] 2 , there exists a polygon with corners at rational coordinates such that for every p ∈ [0, 1] 2 , there is a set of guards of minimum cardinality containing p if and only if p ∈ S . In the ∃ ℝ-hardness proof for the AGP, we introduce a new ∃ ℝ-complete problem ETR-INV. We believe that this problem is of independent interest, as it has already been used to obtain ∃ ℝ-hardness proofs for other problems.

Drawing Possibility

This chapter describes the collaboration between the Department of Indigenous Education in the Faculty of Education at the University of Victoria in British Columbia, Canada and the extension program at the Art Gallery of Greater Victoria, illustrating the process of engaging pre-service teachers working in collaboration with Indigenous artists, staff from the Art Gallery, and learners in the schools where art-based workshops were facilitated. Further, it will describe how by being involved on this project, the student teachers were able to reflect on themselves as educators, and on the challenges and triumphs that entails doing decolonizing work and becoming allies, advocates or “Indigenists.”

On the works of Nicholas K. Roerich in the Primorye State Art Gallery

В статье, основанной на материалах многолетних исследований автора, рассматриваются два произведения Николая Константиновича Рериха из собрания Приморской государственной картинной галереи. Внимание заостряется на причастности пейзажа «Туман» (1907) к серии «Финляндских этюдов» художника, а этюда «Дорожка» (1908) — к известной петербургской коллекции, в 1910-е годы принадлежавшей А.В. и Е.Л. Румановым. В настоящее время коллекция Румановых рассеяна по двадцати пяти государственным музеям бывшего Советского Союза. Больше всего произведений входит в собрание Русского музея. В Приморской картинной галерее хранится всего одна работа — этюд Рериха «Дорожка», и по ней довольно сложно судить о масштабе коллекции Румановых и месте данного этюда в числе других работ художника, входивших в ее состав. Уточнение истории создания и бытования обоих пейзажей Н.К. Рериха из собрания Приморской картинной галереи имеет важное значение для их изучения и научной каталогизации, а также для просветительской деятельности галереи. The article, based on the materials of the author's long-term research, examines two works by Nicholas Konstantinovich Roerich from the collection of the Primorye State Art Gallery. Attention is focused on the involvement of the landscape “Fog” (1907) in the series of “Finnish sketches” by the artist, and the sketch “Path” (1908) — in the famous St. Petersburg collection, in the 1910s owned by A.V. and E.L. Rumanov. Currently, the Rumanov collection is scattered across twenty-five state museums of the former Soviet Union. Most of the works are included in the collection of the Russian Museum. The Primorye Art Gallery has only one work — Roerich's sketch “The Path”, and it is quite difficult to judge the scale of the Rumanov collection and the place of this sketch among other works of the artist that were part of it. Clarification of the history of the creation and existence of both landscapes by N.K. Roerich from the collection of the Primorye Art Gallery is important for their study and scientific cataloging, as well as for the educational activities of the gallery.

Examination and Attribution of Carrying the Cross from the Collection of the Borys Voznytsky Lviv National Art Gallery

Examination and Attribution of Carrying the Cross from the Collectionof the Borys Voznytsky Lviv National Art Gallery

The history of the opening of the first exhibition from the Republic of Korea in the Primorye State Art Gallery

Статья посвящена истории открытия персональной выставки художника Ким Кён Ёл (Kim Kyong Yeoul) из Республики Корея в Приморской картинной галерее в 1997 году и ее значению для развития российско-корейских культурных связей. В основу исследования положены материалы из коллекции и архива Приморской государственной картинной галереи. Primorye State Art Gallery The article is devoted to the history of the opening of the exhibition of Korean artist Kim Kyong Yeoul (Seoul, Pepublic of Korea) in the Primorye State Art Gallery in 1997 and to its significance for the Russian-Korean cultural relations. This research is based on the Primorye State Art Gallery‘s collection and archive.

On the attribution of the portrait of Emperor Peter III by the German artist Georg Christoph (Christoph) Groot from the funds of the Primorye State Art Gallery

Статья является результатом исследования, проведенного в рамках работы над научным каталогом «Русская живопись XVIII – первой половины XIX века в собрании Приморской картинной галереи». Многие десятилетия никто не пересматривал «традиционную» атрибуцию «Портрета императора Петра III» кисти немецкого художника Георга Христофа (Кристофа) Гроота. И только при работе над каталогом авторство Г.Х. Гроота подверглось сомнению. Автор статьи опирается на классические методы исследования в искусствоведении: стилистический анализ, технико-технологическую экспертизу. The article presents the result of research carried out during the work on the scientific catalogue “Russian Painting of the 18th – first half of the 19th century in the collection of the Primorye State Art Gallery”. For many decades, no one revisited “traditional” attribution of the portrait of Emperor Peter III by the German artist Georg Christoph (Christoph) Groot. And only when working on the catalogue, the Georg Christoph Grooth’s authorship was questioned. The author of the article relies on classical research methods in art history: stylistic analysis, technical and technological expertise.

The Jewish Coins at Dura-Europos

The synagogue at Dura-Europos is undoubtedly the most prominent of the Jewish remains uncovered at the site. Dozens of Jewish coins found in excavations throughout the city have merited far less attention. Alfred Bellinger published a list of these coins in 1949; among the corpus of 14,017 coins found altogether at the site, 47 were identified as coins minted in Judea by Jewish rulers. This study offers the first comprehensive presentation and analysis of these Jewish coins. Following a review and analysis of the limited data on all 47 Jewish coins published in the original report, a full report is presented for the six coins from the Dura collection which are currently housed at the Yale University Art Gallery. This is followed by a discussion about the possible reasons why such a large assemblage of Jewish coins found its way in antiquity from Judea to distant Dura-Europos.

Creating Community During COVID-19: A Virtual Art Gallery to Address Social Isolation During a Pandemic

The COVID-19 pandemic, a public health crisis, significantly impacted millions of people around the world. “Creating Community During COVID-19” is a community-engaged virtual art gallery that explores resilience, social cohesion, and creativity during the onset of the pandemic in the United States. It aimed to address social isolation and encourage inclusion at a large public university in the early days of the pandemic. The community was invited to submit artworks that reflected how they are staying connected during the pandemic. The artworks were then qualitatively analyzed and highlighted three key themes: (1) reflecting (turning inward), (2) advocating (turning outward), and (3) engaging (coming together). This arts-based project demonstrates promise as a creative approach for promoting social cohesion and positive health and well-being, especially in times of uncertainty.

The Upihoi find: Wrecked wooden Bevaia (Lagatoi) hulls of Epemeavo Village, Gulf Province, Papua New Guinea

On 20 August 2007, Epemeavo and Kea Kea villagers from the eastern end of the Gulf Province of Papua New Guinea reported finding two lagatoi hulls deeply buried in beach sands at Upihoi, near Epemeavo village, parts of a trading vessel associated with the renowned Motu hiri trade of former times. This paper presents results of an emergency investigation of these finds by staff of the Papua New Guinea National Museum and Art Gallery and Monash University, describing the find, its environmental, cultural and social settings and contexts of discovery, radiocarbon dating, historical assessments, and significance.

Computer Network Information Security Protection Faced by Digital Art Museums Based on the Internet of Things

The development of the Internet of things provides a great opportunity for the development of all walks of life, but it also brings many risks in the process, of which the most important thing is the protection of computer network information security. Digital art museums play a great role in viewing, education, and other functions. This article is aimed at analyzing the computer network information security protection problems faced by digital art museums. Analyze the application of the digital art gallery in the computer Internet of things, and combine the different aspects involved in the two parts to carry out experimental analysis and comparison. The difference between the various subjects of the digital art gallery, such as exhibits, writers, and visitors, is to maintain the security of Internet computer information. Introduce the application. The results show that compared with that of fog computing technology and that of edge computing technology, the performance of the Internet of things is generally better, with faster data processing speed, shorter processing time, higher quality, and stronger scalability. But at the same time, it is also facing greater computer network security threats. According to statistics, 83.3% of consumers worry about its usability but people are more concerned about its safety performance. Nearly 87.5% of consumers worry about whether their information will be leaked. When cloud computing technology is applied to digital art museums, how to protect computer network information security is particularly important. Based on the traditional firewall, this paper designs a hybrid firewall, which can better solve the problem of computer network information security.