Damiano Anselmi, 2019. — 148 p., illus. The discoveries made in physics during the past one hundred years provide answers to the deepest questions we may ask ourselves (who are we?, where do we come from?, what is the purpose of life?, what is the origin of the world?, what is the meaning of everything?). Presenting the key principles of quantum mechanics in a brand new light...
Cambridge University Press, 2021. — 720 p. — ISBN 978-1-107-16887-9. The holy grail of theoretical physics is to find the theory of everything that combines all the forces of nature, including gravity. This book addresses the question: how far are we from such discovery? Over the last few decades, multiple roads to finding a quantum theory of gravity have been proposed but no...
World Scientific, 1991. — 325 p. — Series: Advanced Series in Astrophysics and Cosmology ISBN10: 9810205740 ISBN13: 978-9810205744 ". provides an excellent, up-to-date account of his reformulation of general relativity and of the new approaches to canonical quantum gravity that it has suggested. The book is well organized and well written. is very successful in achieving its...
World Scientific Publishing Co. Pte. Ltd., 2017. — 320 p. — (100 Years of General Relativity. Vol. 4) — ISBN: 9813209925. A hundred years ago, Einstein unveiled his final formulation of general relativity. Perhaps the deepest feature of this theory is the encoding of the gravitational interaction in the very geometry of spacetime. Thus, general relativity required that we...
Birkhäuser, 1991. — 602 pp. — (Einstein Studies, Vol. 2) Quantum Mechanics, Measurement, and the Universe Einstein and Quantum Mechanics (by John Stachel). Quantum Measurements and the Environment-Induced Transition from Quantum to Classical (by Wojciech Zurek). Loss of Quantum Coherence for a Damped Oscillator (by W. G. Unruh). The Wheeler-DeWitt Equation and the Path Integral in...
Springer-Verlag Berlin Heidelberg, 2000 — 152p. — (Lecture Notes in Physics Monographs 64) — ISBN: 978-3-540-46523-2 (eBook), 978-3-642-08646-5 (Softcover), 978-3-540-67155-8 (Hardcover). This book tackles quantum gravity via the so-called background field method and its effective action functional. The author presents an explicitly covariant and effective technique to...
Oxford University Press, 1994. — 248 p. — (Oxford Lecture Series in Mathematics and Its Applications). — ISBN 0198534906. Recent work by mathematicians and physicists has uncovered revelatory connections between knot theory and the problem of developing a quantum theory of gravity. This book, the proceedings of a workshop held to bring together researchers in knot theory and...
Oxford University Press, 2018. — 448 p. — ISBN: 978–0–19–880911–1. Today we are blessed with two extraordinarily successful theories of physics. The first is Albert Einstein's general theory of relativity, which describes the large-scale behaviour of matter in a curved spacetime. This theory is the basis for the standard model of big bang cosmology. The discovery of...
Springer, 2025. — 4314 p. — ISBN 9819976804. The search for a theory of quantum gravity is one of the most important and fascinating problems in modern theoretical physics. While we do not have yet a complete theory of quantum gravity, significant advancements have been done in the past decades. In this handbook, every section is dedicated to a specific approach towards a...
2nd. ed. - Springer, 2024. - 209 p. - ISBN 303143451X. This second edition offers a comprehensive introduction to loop quantum gravity (LQG) in self-dual variables, including the necessary prerequisites. Additionally, it delves into various significant research areas that have emerged in recent years. New content (including an entirely new chapter dedicated to dynamics of...
Faculty of Physics, University of Warsaw, arXiv, 2016. — 62 p. An introduction to loop quantum gravity is given, focussing on the fundamental aspects of the theory, different approaches to the dynamics, as well as possible future directions. It is structured in five lectures, including exercises, and requires only little prior knowledge of quantum mechanics, gauge theory, and...
Springer-Verlag Berlin Heidelberg, 2010. — 350 p. — (Lecture Notes in Physics 807). — ISBN: 978-3-642-11897-5 (eBook), 978-3-642-11896-8 (Softcover). Aside from the obvious statement that it should be a theory capable of unifying general relativity and quantum field theory, not much is known about the true nature of quantum gravity. New ideas - and there are many of them for...
Springer, 2012. - 399 pp. Quantum gravity has developed into a fast-growing subject in physics and it is expected that probing the high-energy and high-curvature regimes of gravitating systems will shed some light on how to eventually achieve an ultraviolet complete quantum theory of gravity. Such a theory would provide the much needed information about fundamental problems of...
Cambridge University Press, 2003, 276 pages This timely volume provides a broad survey of (2+l)-dimensional quantum gravity. It emphasises the 'quantum cosmology' of closed universes and the quantum mechanics of the (2+l)-dimensional black hole. It compares and contrasts a variety of approaches, and examines what they imply for a realistic theory of quantum gravity. General...
Adam Higler Ltd., 1984. — 497 p. The 33 essays in this volume together provide a valuable overview of the progress towards a theory of quantum gravity, and offer succinct treatment of quantum field theory in curved space-times, supergravity, cosmology, black holes, quantum geometry, supersymmetry and related phenomena.
World Scientific Publishing Company, 2014. — 200 p. This book aims to present a pedagogical and self-consistent treatment of the canonical approach to Quantum Gravity, starting from its original formulation to the most recent developments in the field. We start with an innovative and enlightening introduction to the formalism and concepts on which General Relativity has been...
World Scientific, 2005. — 386 p. Three key aspects of quantum gravity are considered in this book: phenomenology, potential experimental aspects and foundational theory. The phenomenology is the treatment of metric quantum fluctuations as torsional curves that deviate from classical expectations. This leads to possible experimental configurations that may detect such fluctuations....
Springer, 2016. – 209 p. – ISBN10: 3319395068 This book discusses the notion that quantum gravity may represent the "breakdown" of spacetime at extremely high energy scales. If spacetime does not exist at the fundamental level, then it has to be considered "emergent", in other words an effective structure, valid at low energy scales. The author develops a conception of...
Cambridge University Press, 2025. — 100 p. The search for a new scientific theory is typically prompted by an encounter with something in the world that cannot be explained by current theories. This is not the case for the search for a theory of quantum gravity, which has been primarily motivated by theoretical and philosophical concerns. This Element introduces some of the...
Springer, 2023. — 79 p. Preface Acknowledgements Acronyms Introduction to Instabilities and Some Relevant Examples Introduction Warm Up Examples Common Types of Instabilities and Their Physical Implications Stable Case Tachyonic Instability: Problems with Low-Momentum Modes Gradient/Laplacian Instability: Problems with High-Momentum Modes Ghostly Instabilities Generalization...
Springer, 2011, 159 pages 1946 is the year Bryce DeWitt entered Harvard graduate school. Quantum Gravity was his goal and remained his goal throughout his lifetime until the very end. The pursuit of Quantum Gravity requires a profound understanding of Quantum Physics and Gravitation Physics. As G. A. Vilkovisky commented , "Quantum Gravity is a combination of two words, and one...
Springer, 1994. — 377 p. The search for a quantum gravity theory, a theory expected to combine the principles of general relativity and quantum theory, has led to some of the most deepest and most difficult conceptual and mathematical questions of modern physics. The present book, addressing these issues in the framework of recent versions of canonical quantization, is the first...
Birkhäuser Basel, 2007 — 336p. — ISBN: 978-3-7643-7978-0 (eBook), 978-3-7643-7977-3 (Hardcover). The construction of a quantum theory of gravity is the most fundamental challenge confronting contemporary theoretical physics. The different physical ideas which evolved while developing a theory of quantum gravity require highly advanced mathematical methods. This book presents...
Springer, 2020. — 302 p. — ISBN: 978-3-030-38940-6. This book focuses on a critical discussion of the status and prospects of current approaches in quantum mechanics and quantum field theory, in particular concerning gravity. It contains a carefully selected cross-section of lectures and discussions at the seventh conference “Progress and Visions in Quantum Theory in View of...
Springer Basel AG, 2012, 380 pages, ISBN: 3034800428 One of the most challenging problems of contemporary theoretical physics is the mathematically rigorous construction of a theory which describes gravitation and the other fundamental physical interactions within a common framework. The physical ideas which grew from attempts to develop such a theory require highly advanced...
Springer International Publishing AG, 2018. — 346 p. — (Lecture Notes in Physics 944) — ISBN: 3319711075. This advanced course, a sequel to the first volume of this lecture series on topos quantum theory, delves deeper into the theory, addressing further technical aspects and recent advances. These include, but are not limited to, the development of physical quantities and...
Springer International Publishing AG, 2018. — 328 p. — (Lecture Notes in Physics 944) — ISBN: 3319711075. This advanced course, a sequel to the first volume of this lecture series on topos quantum theory, delves deeper into the theory, addressing further technical aspects and recent advances. These include, but are not limited to, the development of physical quantities and...
Springer, 2013. — 449 p. In the last five decades various attempts to formulate theories of quantum gravity have been made, but none has fully succeeded in becoming the quantum theory of gravity. One possible explanation for this failure might be the unresolved fundamental issues in quantum theory as it stands now. Indeed, most approaches to quantum gravity adopt standard...
Revised Edition. — Independently Published, 2020. — 269 p. — ISBN13: 979-8663896528. This math-free book is a good introduction to quantum gravity and has a lot of interesting history about the development of the theory since 1899. It's an informal introduction to a very difficult and doubtfully intelligible theory.- doubted even by its most ingenious contributors. The reader...
Cambridge University Press, 2012. — 607 p. Supergravity, together with string theory, is one of the most significant developments in theoretical physics. Although there are many books on string theory, this is the first-ever authoritative and systematic account of supergravity. Written by two of the most respected workers in the field, it provides a solid introduction to the...
Oxford University Press, Inc., New York, 2011. — 192 p. — ISBN: 9780199590759. Loop quantum gravity has emerged as a possible avenue towards the quantization of general relativity. Looking at the top 50 cited papers of all time of the arXiv.org:gr-qc preprint repository (which includes papers on gravity as a whole, not only quantum gravity); according to the SPIRES database in...
World Scientific, 2020. — 104 pp. Loop quantum gravity is one of the main contenders to unify Einstein's general theory of relativity and quantum mechanics, therefore providing a quantum theory of gravity. If these words do not mean much to you, do not worry, we will define them in simple terms. This book describes loops quantum gravity and its applications to cosmology, black...
Cambridge University Press, 2022. — 337 p. — (Cambridge Monographs on Mathematical Physics). — ISBN 978-1-009-29019-3. This volume provides a self-contained introduction to applications of loop representations, and the related topic of knot theory, in particle physics and quantum gravity. These topics are of considerable interest because they provide a unified arena for the...
Cambridge University Press, 2000. - 321 pp.
Loop representations (and the related topic of knot theory) are of considerable current interest because they provide a unified arena for the study of the gauge invariant quantization of Yang-Mills theories and gravity, and suggest a promising approach to the eventual unification of the four fundamental forces. This text provides a...
Cambridge University Press, 2017. — 453 p. — (Cambridge Monographs On Mathematical Physics) — ISBN: 9781107147898. This book project over a period of many years in order to create a concise but comprehensive account of exact solutions in the threedimensional Einstein theory of gravity. This theory, although tangentially related to the real gravity world, is a good model from...
Springer International Publishing AG, 2018. — 204 p. — (Fundamental Theories of Physics 194). — ISBN: 3319773704. A unified quantum theory incorporating the four fundamental forces of nature is one of the major open problems in physics. The Standard Model combines electro-magnetism, the strong force and the weak force, but ignores gravity. The quantization of gravity is...
2nd. ed. - Springer, 2024. - 268 p. - (Fundamental Theories of Physics, 194). - ISBN 3031679210. A unified quantum theory incorporating the four fundamental forces of nature is one of the major open problems in physics. The Standard Model combines electro-magnetism, the strong force and the weak force, but ignores gravity. The quantization of gravity is therefore a necessary...
World Scientific, 1993. — 595 p. The 1960's and early 1970's was a period of rapid development for the classical theory of general relativity. Stimulated by the experimental discoveries of quasars, pulsars and the cosmic microwave background, attention turned to the problem of the gravitational collapse of stars and more massive beodies and to the problem of the big bang.
Springer,2003, 394 p. This book gives readers a comprehensive introduction accessible to interested non-experts to the main issues surrounding the search for quantum gravity. These issues relate to fundamental questions concerning the various formalisms of quantization; specific questions concerning concrete processes, like gravitational collapse or black-hole evaporation; and the...
Santa Barbara (USA): Springer Science+Business Media, 2004. — 349 p. — ISBN: 0-387-23995-2. Лекции по квантовой гравитации (на англ.яз.). Series of the Centro de Estudios Cientificos. Edited by Andres Gomberoff (Centro de Estudios Cientificos, Valdivia, Chile), Donald Marolf (University of California, Santa Barbara). The 2002 Pan-American Advanced Studies Institute School on...
Springer, 2017. — 144 p. This thesis studies various aspects of non-critical strings both as an example of a non-trivial and solvable model of quantum gravity and as a consistent approximation to the confining flux tube in quantum chromodynamics (QCD). It proposes and develops a new technique for calculating the finite volume spectrum of confining flux tubes. This technique is...
Springer-Verlag, Berlin, Heidelberg, 2009. — 352 p.
Continuum Formulation
General Aspects
Massless Spin Two Field
Wave Equation
Feynman Rules
One-Loop Divergences
Gravity in d Dimensions
Higher Derivative Terms
Supersymmetry
Supergravity
String Theory
Supersymmetric Strings
Feynman Path Integral Formulation
The Path Integral
Sum over Paths
Eulidean Rotation...
Reviews of Modern Physics, Vol. 88, 015002 (58 pp.), 2016. These lectures give an introduction to the quantum physics of black holes, including recent developments based on quantum information theory such as the firewall paradox and its various cousins. An introduction is also given to holography and the anti–de Sitter/conformal field theory (AdS/CFT) correspondence, focusing...
Princeton University Press, 2010. — x, 145 p. — (The Isaac Newton institute series of lectures). — ISBN: 0-691-03791-4, 978-0-691-14570-9. Einstein said that the most incomprehensible thing about the universe is that it is comprehensible. But was he right? Can the quantum theory of fields and Einstein’s general theory of relativity, the two most accurate and successful theories...
Princeton University Press, 2010. — 155 p. — (The Isaac Newton institute series of lectures). — ISBN 0-691-03791-4, 978-0-691-14570-9. Einstein said that the most incomprehensible thing about the universe is that it is comprehensible. But was he right? Can the quantum theory of fields and Einstein’s general theory of relativity, the two most accurate and successful theories in...
Springer International Publishing AG, 2018. — 121 p. — (FIAS Interdisciplinary Science Series) — ISBN: 3319645366. This book summarizes recent developments in the research area of quantum gravity phenomenology. A series of short and nontechnical essays lays out the prospects of various experimental possibilities and their current status. Finding observational evidence for the...
Cambridge University Press, 2020. — viii, 362 p. — ISBN: 978-1-108-47702-4. True PDF One of the greatest challenges in fundamental physics is to reconcile quantum mechanics and general relativity in a theory of quantum gravity. A successful theory would have profound consequences for our understanding of space, time, and matter. This collection of essays written by eminent...
Frankfurt am Main, Germany: Clausen & Bosse, Leck, 2003. — 132 p. — ISBN: 3596153573. Die Gravitation ist die älteste der bekannten Wechselwirkungen und aus dem Alltag wohlvertraut. Ihr Name leitet sich von dem lateinischen Wort gravitas (Schwere) ab. Sie ist nicht nur dafür verantwortlich, dass losgelassene Gegenstände auf den Boden fallen, sondern hält auch die Planeten auf...
2nd ed. — Oxford University Press, 2007. — 374 p. The construction of a consistent theory of quantum gravity continues to be the major open problem in fundamental physics. The unification of quantum theory with Einstein’s theory of general relativity is perhaps the biggest open problem of theoretical physics. Such a theory is not only needed for conceptual reasons, but also for...
Philosophy Documentation Center, Western University-Canada, 2017. 32 p. ISSN: 1330-0016 In the paper, with the help of various models, the thesis on the fundamental nature of the field form of matter in physics is considered. In the first chapter a model of special relativity is constructed, on the basis of which the priority of the massless form of matter is revealed. In the...
Springer-Verlag Berlin Heidelberg, 2005. — 414 p. — (Lecture Notes in Physics 669). — ISBN: 978-3-540-31527-8 (eBook), 978-3-642-06441-8 (Softcover), 978-3-540-25263-4 (Hardcover). This volume is composed of extensive and detailed notes from the lectures given at the 40th Karpacz Winter School. This school focussed on quantum gravity phenomenology with emphasis on its relation...
Cambridge University Press, 2013. — 416 p. Exploring how the subtleties of quantum coherence can be consistently incorporated into Einstein's theory of gravitation, this book is ideal for researchers interested in the foundations of relativity and quantum physics. The book examines those properties of coherent gravitating systems that are most closely connected to experimental...
Springer US; Plenum Press, 1984. — 543 p. — ISBN-13 9781461327011. Three years have passed after the First Moscow Seminar on Quantum Gravity. It is a rather long time interval for the modern theoretical physics. The talks given at the present Second Seminar which took place in October 13-15, 1981 in Moscow contain the discussion of new results obtained during this period and...
Nova Science Publishers, Inc., NY, 2017. — 173 p. — ISBN: 1536107980. This book provides new research on quantum gravity. Chapter One reviews the semi-classical corrections to the metric of a spherically symmetric static black hole space-time. Chapter Two discusses quantum entanglement in connection to black holes and nanotechnology. Chapter Three provides a particle-like...
Bristol: Iop Publishing, 2020. — 114 p. The development of a successful theory of quantum gravity in the context of the early universe is the key next step in theoretical physics. This book takes that step by describing a coherent mathematical framework for both the evolution of discrete space-time and the quantum graviton in the Planck regime. In doing so it successfully...
Cambridge University Press, 2007. This is the first introductory textbook on quantum field theory in gravitational backgrounds intended for undergraduate and beginning graduate students in the fields of theoretical astrophysics, cosmology, particle physics, and string theory. The book covers the basic (but essential) material of quantization of fields in expanding universe and...
Cambridge University Press, 2009. - 583 pp. The theory of quantum gravity promises a revolutionary new understanding of gravity and spacetime, valid from microscopic to cosmological distances. Research in this field involves an exciting blend of rigorous mathematics and bold speculations, foundational questions and technical issues. Containing contributions from leading...
World Scientific Publishing Co. Pte. Ltd., 2017. — 313 p. — (100 Years of General Relativity 3) — ISBN: 9813207175. This book covers recent developments in the covariant formulation of quantum gravity. Developed in the 1960s by Feynman and DeWitt, by the 1980s this approach seemed to lead nowhere due to perturbative non-renormalizability. The possibility of non-perturbative...
Springer, 2020. — 77 p. — (Springer Briefs in Physics). — 10.1007/978-3-031-46634-2 This review presents itself as a collection of the lecture notes on modified gravity based on lectures given at UFPB (Joao Pessoa, Brazil), CBPF (Rio de Janeiro, Brazil), UFC (Fortaleza, Brazil), and Universidad del Bio-Bio (Concepcion, Chile). General relativity (GR) is clearly one of the most...
World Scientific Publishing Co. Pte. Ltd, 1995. — 382 p. — ISBN10: 9810220774 This monograph explains and analyzes the principles of a quantum-geometric framework for the unification of general relativity and quantum theory. By taking advantage of recent advances in areas like fibre and superfibre bundle theory, Krein spaces, gauge fields and groups, coherent states, etc.,...
Cambridge University Press, 2019. — 354 p. — (Cambridge Monographs on Mathematical Physics). — ISBN: 1107107326. During the past two decades the gravitational asymptotic safety scenario has undergone a major transition from an exotic possibility to a serious contender for a realistic theory of quantum gravity. It aims at a mathematically consistent quantum description of the...
Oxford University Press, 2006. — 282 p. — ISBN: 978–0–19–926969–3. What is spacetime? General relativity and quantum field theory answer this question in very different ways. This collection of essays by physicists and philosophers looks at the problem of uniting these two most fundamental theories of our world, focusing on the nature of space and time within this new quantum...
Singapore: World Scientific Publishing Company, 2021. — 181 p. Currently, the General Theory of Relativity (GTR) describes the physics of the very large in terms of classical physics, while quantum theory describes the physics of the very small in terms of the Standard Model of particle physics. Unfortunately, the two theories are incompatible and do not describe satisfactorily...
Cambridge University Press, 2007 — 488 pp. — (Cambridge Monographs on Mathematical Physics). — ISBN: 9780521715966. Quantum gravity poses the problem of merging quantum mechanics and general relativity, the two great conceptual revolutions in the physics of the twentieth century. The loop and spinfoam approach, presented in this book, is one of the leading research programs in...
Draft version,30 December 2003, 347 p. The problem of quantum gravity has many aspects. Ideas and results are scattered in the literature. In this book I have attempted to collect the main results and to present an overall perspective on quantum gravity, as developed during this period. The point of view is personal and the choice of subjects is determined by my own interests....
Pengium Random House, UK, 2016. — 165 p. — ISBN: 9780241257975 “The man who makes physics sexy...the scientist they’re calling the next Stephen Hawking.” —The Times Magazine From the New York Times–bestselling author of Seven Brief Lessons on Physics, a closer look at the mind-bending nature of the universe. What are time and space made of? Where does matter come from? And what...
Pengium Random House, UK, 2016. — 262 p. — ISBN-13 9789386057457. “The man who makes physics sexy...the scientist they’re calling the next Stephen Hawking.” —The Times Magazine From the New York Times–bestselling author of Seven Brief Lessons on Physics, a closer look at the mind-bending nature of the universe. What are time and space made of? Where does matter come from? And...
Cambridge University Press, 2014. — 266 pp. — ISBN: 9781107069626. Quantum gravity is among the most fascinating problems in physics. It modifies our understanding of time, space and matter. The recent development of the loop approach has allowed us to explore domains ranging from black hole thermodynamics to the early Universe. This book provides readers with a simple...
Cambridge University Press, 2010. — 485 p. — ISBN 978-0-521-71596-6. Quantum gravity is perhaps the most important open problem in fundamental physics. It is the problem of merging quantum mechanics and general relativity, the two great conceptual revolutions in the physics of the twentieth century. The loop and spinfoam approach, presented in this 2004 book, is one of the...
Springer, 2020. — 139 p. — (Springer Geophysics). — ISBN 978-3-030-42837-2. During the last thirty years a great advancement in low energy physics, particularly interactions of atoms with the electromagnetic field, has been achieved and the development of electronics and laser techniques has allowed to implement a fine manipulation of atoms with photons. A wealth of important...
Springer Japan, 2014 — 100p. — (Springer Theses) — ISBN: 978-4-431-54947-5 (eBook), 978-4-431-56225-2 (Softcover), 978-4-431-54946-8 (Hardcover). In this thesis, the author considers quantum gravity to investigate the mysterious origin of our universe and its mechanisms. He and his collaborators have greatly improved the analyticity of two models: causal dynamical...
A Member of the Perseus Books Group, Great Britian, 2001. – 255 p. – ISBN: 0465078362 The Holy Grail of modern physics is a theory of the universe that unites two seemingly opposing pillars of modern science: Einstein's theory of general relativity, which deals with large-scale phenomena (planets, solar systems and galaxies), and quantum theory, which deals with the world of...
InTech, 2012, 100 pages, ISBN: 9535100898 9789535100898 This book presents a series of selected chapters written by renowned authors with the objective to provide an overview and comparison of the various quantum gravity theories. Each chapter treats gravity and its quantization through known and alternative techniques, aiming a deeper understanding on the quantum nature of...
Albert-Einstein-Institut (Germany), 2002. — 92 p. OCR
Quantum General Relativity (QGR), sometimes called Loop Quantum Gravity, has matured over the past fifteen years to a mathematically rigorous candidate quantum field theory of the gravitational field. The features that distinguish it from other quantum gravity theories are 1) background independence and 2) minireality of...
New York, "Cambridge University Press". 2007, -846p. Modern physics rests on two fundamental building blocks: general relativity and quantum theory. General relativity is a geometric interpretation of gravity, while quantum theory governs the microscopic behaviour of matter. According to Einstein’s equations, geometry is curved when and where matter is localized. Therefore, in...
Springer International Publishing, 2017 — 138p. — ISBN: 978-3-319-43184-0 (eBook), 978-3-319-43182-6 (Softcover). This primer offers a concise introduction to Loop Quantum Gravity (LQG) - a theoretical framework for uniting Quantum Mechanics (QM) with General Relativity (GR). The emphasis is on the physical aspects of the framework and its historical development in terms of...
Саратов: СГУ, 2012. — 24 с. Цель данного учебного пособия – познакомить студентов/аспирантов с основными фактами и понятиями теории суперструн и многомерных теорий гравитации. Теоретические и практические результаты данной работы рекомендуются для использования при преподавании учебного курса «Квантовая гравитация» для магистров по профилю подготовки «Теоретическая физика»....
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