Projective unitary groupIn mathematics, the projective unitary group PU(n) is the quotient of the unitary group U(n) by the right multiplication of its center, U(1), embedded as scalars. Abstractly, it is the holomorphic isometry group of complex projective space, just as the projective orthogonal group is the isometry group of real projective space. In terms of matrices, elements of U(n) are complex n×n unitary matrices, and elements of the center are diagonal matrices equal to eiθ multiplied by the identity matrix.
SustainabilitySustainability is a social goal for people to co-exist on Earth over a long time. Specific definitions of this term are disputed and have varied with literature, context, and time. Experts often describe sustainability as having three dimensions (or pillars): environmental, economic, and social, and many publications emphasize the environmental dimension. In everyday use, sustainability often focuses on countering major environmental problems, including climate change, loss of biodiversity, loss of ecosystem services, land degradation, and air and water pollution.
Algebraic groupIn mathematics, an algebraic group is an algebraic variety endowed with a group structure that is compatible with its structure as an algebraic variety. Thus the study of algebraic groups belongs both to algebraic geometry and group theory. Many groups of geometric transformations are algebraic groups; for example, orthogonal groups, general linear groups, projective groups, Euclidean groups, etc. Many matrix groups are also algebraic. Other algebraic groups occur naturally in algebraic geometry, such as elliptic curves and Jacobian varieties.
CityA city is a human settlement of a notable size. It can be defined as a permanent and densely settled place with administratively defined boundaries whose members work primarily on non-agricultural tasks. Cities generally have extensive systems for housing, transportation, sanitation, utilities, land use, production of goods, and communication. Their density facilitates interaction between people, government organizations, and businesses, sometimes benefiting different parties in the process, such as improving the efficiency of goods and service distribution.
Smart cityA smart city is a technologically modern urban area that uses different types of electronic methods and sensors to collect specific data. Information gained from that data is used to manage assets, resources and services efficiently; in return, that data is used to improve operations across the city. This includes data collected from citizens, devices, buildings and assets that is processed and analyzed to monitor and manage traffic and transportation systems, power plants, utilities, water supply networks, waste, criminal investigations, information systems, schools, libraries, hospitals, and other community services.
ShanghaiShanghai (ʃæŋˈhaɪ; , zɑ̃̀.hɛ́zh-wuu-2-上海.ogg, Standard Mandarin pronunciation: AUDZh-Shanghai.oggshang4.hai3) is one of the four direct-administered municipalities of the People's Republic of China (PRC). The city is located on the southern estuary of the Yangtze River, with the Huangpu River flowing through it. The population of the city proper is the third most populous in the world, with 24.89 million inhabitants in 2021, while the urban area is the most populous in China, with 39,300,000 residents.
Shanghai cliqueThe Shanghai clique (), also referred to as the Shanghai gang, Jiang clique, or Jiang faction, refers to an informal group of Chinese Communist Party (CCP) officials who rose to prominence under former CCP General Secretary Jiang Zemin while he served as the party chief and mayor of Shanghai. Chinese politics have long been defined by the competition between intra-party factions' ability to place key members and allies in positions of power within the CCP and Chinese government.
Human rightsHuman rights are moral principles or norms for certain standards of human behaviour and are regularly protected in municipal and international law. They are commonly understood as inalienable, fundamental rights "to which a person is inherently entitled simply because she or he is a human being" and which are "inherent in all human beings", regardless of their age, ethnic origin, location, language, religion, ethnicity, or any other status.
HumanHumans, or modern humans (Homo sapiens), are the most common and widespread species of primate. A great ape characterized by their hairlessness, bipedalism, and high intelligence, humans have a large brain and resulting cognitive skills that enable them to thrive in varied environments and develop complex societies and civilizations. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states.
FloodA flood is an overflow of water (or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrology and are of significant concern in agriculture, civil engineering and public health. Human changes to the environment often increase the intensity and frequency of flooding, for example land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees, and larger environmental issues such as climate change and sea level rise.
Urban renewalUrban renewal (also called urban regeneration in the United Kingdom and urban redevelopment in the United States) is a program of land redevelopment often used to address urban decay in cities. Urban renewal involves the clearing out of blighted areas in inner cities to clear out slums and create opportunities for higher class housing, businesses, and other developments. A primary purpose of urban renewal is to restore economic viability to a given area by attracting external private and public investment and by encouraging business start-ups and survival.
Natural disasterA natural disaster is the highly harmful impact on a society or community following a natural hazard event. Some examples of natural hazard events include: flooding, drought, earthquake, tropical cyclone, lightning, tsunami, volcanic activity, wildfire. A natural disaster can cause loss of life or damage property, and typically leaves economic damage in its wake. The severity of the damage depends on the affected population's resilience and on the infrastructure available.
