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Rimhak Ree
Rimhak Ree (alternative spelling: Im-hak Ree, December 18, 1922 – January 9, 2005) was a Korean Canadian mathematician. He contributed in the field of group theory, most notably with the concept of the Ree group in . Early life Ree received his early education in Hamhung, South Hamgyong, in what is now North Korea; he attended the Hamhung #1 Public Ordinary School (), and in 1934 entered the Hamhung Public High School (). He went onto Keijō Imperial University, where he studied physics, which was an unusual choice for Koreans at the time. Ree graduated in 1944 with a physics degree; he then went to Fengtian, Manchukuo (today Shenyang, Liaoning in the People's Republic of China) to work for an aircraft company. Career After the surrender of Japan in 1945 and the end of Japanese rule in Korea, Ree returned to his home country and in 1947 took up a teaching position in the mathematics department at Seoul National University as an assistant professor. Later that year, in N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamhung
Hamhŭng (''Hamhŭng-si''; ) is North Korea's second-largest List of cities in North Korea, city, and the capital of South Hamgyong, South Hamgyŏng Province. It has an estimated population of 768,551. Located in the southern part of the South Hamgyong province, Hamhung is the main and most popular metropolitan area in the province. Hamhung has a thriving local economy compared to other metropolitan areas in North Korea, and it is known by North Koreans as a great area of architectural construction that was Planned economy, centrally planned, and built by the government of North Korea. Administrative divisions Hamhŭng is Administrative divisions of North Korea#Second-level divisions, divided into 7 ''guyŏk'' (wards): Geography Hamhŭng is on the left branch of the Songchon River, Sŏngch'ŏn River, on the eastern part of the Hamhŭng plain (), in South Hamgyŏng Province, northeast North Korea. Its highest point is Mount Tonghŭng, which is high. Climate Hamhung has a humi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liaoning
Liaoning () is a coastal province in Northeast China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmost coastal province of the People's Republic of China. Historically a gateway between China proper and Manchuria, the modern Liaoning province was established in 1907 as Fengtian or Fengtien province and was renamed Liaoning in 1929. It was also known at that time as Mukden Province for the Manchu name of ''Shengjing'', the former name of Shenyang. Under the Japanese-puppet Manchukuo regime, the province reverted to its 1907 name, but the name Liaoning was restored for a brief time in 1945 and then again in 1954. Liaoning borders the Yellow Sea ( Korea Bay) and Bohai Sea in the south, North Korea's North Pyongan and Chagang provinces in the southeast, Jilin to the northeast, Hebei to the southwest, and Inner Mongolia to the northwest. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrational Numbers
In mathematics, the irrational numbers (from in- prefix assimilated to ir- (negative prefix, privative) + rational) are all the real numbers that are not rational numbers. That is, irrational numbers cannot be expressed as the ratio of two integers. When the ratio of lengths of two line segments is an irrational number, the line segments are also described as being '' incommensurable'', meaning that they share no "measure" in common, that is, there is no length ("the measure"), no matter how short, that could be used to express the lengths of both of the two given segments as integer multiples of itself. Among irrational numbers are the ratio of a circle's circumference to its diameter, Euler's number ''e'', the golden ratio ''φ'', and the square root of two. In fact, all square roots of natural numbers, other than of perfect squares, are irrational. Like all real numbers, irrational numbers can be expressed in positional notation, notably as a decimal number. In the case ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class (set Theory)
In set theory and its applications throughout mathematics, a class is a collection of sets (or sometimes other mathematical objects) that can be unambiguously defined by a property that all its members share. Classes act as a way to have set-like collections while differing from sets so as to avoid Russell's paradox (see ). The precise definition of "class" depends on foundational context. In work on Zermelo–Fraenkel set theory, the notion of class is informal, whereas other set theories, such as von Neumann–Bernays–Gödel set theory, axiomatize the notion of "proper class", e.g., as entities that are not members of another entity. A class that is not a set (informally in Zermelo–Fraenkel) is called a proper class, and a class that is a set is sometimes called a small class. For instance, the class of all ordinal numbers, and the class of all sets, are proper classes in many formal systems. In Quine's set-theoretical writing, the phrase "ultimate class" is often used in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Erdős
Paul Erdős ( hu, Erdős Pál ; 26 March 1913 – 20 September 1996) was a Hungarian mathematician. He was one of the most prolific mathematicians and producers of mathematical conjectures of the 20th century. pursued and proposed problems in discrete mathematics, graph theory, number theory, mathematical analysis, approximation theory, set theory, and probability theory. Much of his work centered around discrete mathematics, cracking many previously unsolved problems in the field. He championed and contributed to Ramsey theory, which studies the conditions in which order necessarily appears. Overall, his work leaned towards solving previously open problems, rather than developing or exploring new areas of mathematics. Erdős published around 1,500 mathematical papers during his lifetime, a figure that remains unsurpassed. He firmly believed mathematics to be a social activity, living an itinerant lifestyle with the sole purpose of writing mathematical papers with other mathem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montana State University
Montana State University (MSU) is a Public university, public land-grant university, land-grant research university in Bozeman, Montana. It is the state's largest university. MSU offers baccalaureate degrees in 60 fields, master's degrees in 68 fields, and doctoral degrees in 35 fields through its nine colleges. More than 16,700 students attended MSU in fall 2019, taught by 796 full-time and 547 part-time faculty. MSU is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Universities – Very high research activity" and had research expenditures of $129.6 million in 2017. Located on the south side of Bozeman, Montana, Bozeman, the university's campus is the largest in the state. The university's main campus in Bozeman is home to KUSM television, KGLT radio, and the Museum of the Rockies. MSU provides outreach services to citizens and communities statewide through its agricultural experiment station and 60 county and reservation extensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Witt Algebra
In mathematics, the complex Witt algebra, named after Ernst Witt, is the Lie algebra of meromorphic vector fields defined on the Riemann sphere that are holomorphic except at two fixed points. It is also the complexification of the Lie algebra of polynomial vector fields on a circle, and the Lie algebra of derivations of the ring C 'z'',''z''−1 There are some related Lie algebras defined over finite fields, that are also called Witt algebras. The complex Witt algebra was first defined by Cartan (1909), and its analogues over finite fields were studied by Witt in the 1930s. Basis A basis for the Witt algebra is given by the vector fields L_n=-z^ \frac, for ''n'' in ''\mathbb Z''. The Lie bracket of two vector fields is given by : _m,L_n(m-n)L_. This algebra has a central extension called the Virasoro algebra that is important in two-dimensional conformal field theory and string theory. Note that by restricting ''n'' to 1,0,-1, one gets a subalgebra. Taken over th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Busan
Busan (), officially known as is South Korea's most populous city after Seoul, with a population of over 3.4 million inhabitants. Formerly romanized as Pusan, it is the economic, cultural and educational center of southeastern South Korea, with its port being Korea's busiest and the sixth-busiest in the world. The surrounding "Southeastern Maritime Industrial Region" (including Ulsan, South Gyeongsang, Daegu, and some of North Gyeongsang and South Jeolla) is South Korea's largest industrial area. The large volumes of port traffic and urban population in excess of 1 million make Busan a Large-Port metropolis using the Southampton System of Port-City classification . Busan is divided into 15 major administrative districts and a single county, together housing a population of approximately 3.6 million. The full metropolitan area, the Southeastern Maritime Industrial Region, has a population of approximately 8 million. The most densely built-up areas of the city are situated in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Korean War
, date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950) , place = Korean Peninsula, Yellow Sea, Sea of Japan, Korea Strait, China–North Korea border , territory = Korean Demilitarized Zone established * North Korea gains the city of Kaesong, but loses a net total of {{Convert, 1506, sqmi, km2, abbr=on, order=flip, including the city of Sokcho, to South Korea. , result = Inconclusive , combatant1 = {{Flag, First Republic of Korea, name=South Korea, 1949, size=23px , combatant1a = {{Plainlist , * {{Flagicon, United Nations, size=23px United Nations Command, United Nations{{Refn , name = nbUNforces , group = lower-alpha , On 9 July 1951 troop constituents were: US: 70.4%, ROK: 23.3% other UNC: 6.3%{{Cite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Max Zorn
Max August Zorn (; June 6, 1906 – March 9, 1993) was a German mathematician. He was an algebraist, group theorist, and numerical analyst. He is best known for Zorn's lemma, a method used in set theory that is applicable to a wide range of mathematical constructs such as vector spaces, and ordered sets amongst others. Zorn's lemma was first postulated by Kazimierz Kuratowski in 1922, and then independently by Zorn in 1935. Life and career Zorn was born in Krefeld, Germany. He attended the University of Hamburg. He received his PhD in April 1930 for a thesis on alternative algebras. He published his findings in ''Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg''. Zorn showed that split-octonions could be represented by a mixed-style of matrices called Zorn's vector-matrix algebra. Max Zorn was appointed to an assistant position at the University of Halle. However, he did not have the opportunity to work there for long as he was forced to leave German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Mathematical Society
The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, and serves the national and international community through its publications, meetings, advocacy and other programs. The society is one of the four parts of the Joint Policy Board for Mathematics and a member of the Conference Board of the Mathematical Sciences. History The AMS was founded in 1888 as the New York Mathematical Society, the brainchild of Thomas Fiske, who was impressed by the London Mathematical Society on a visit to England. John Howard Van Amringe was the first president and Fiske became secretary. The society soon decided to publish a journal, but ran into some resistance, due to concerns about competing with the American Journal of Mathematics. The result was the ''Bulletin of the American Mathematical Society'', with Fiske as editor-in-chief. The de facto journal, as intended, was influential in in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Namdaemun Market
Namdaemun Market is a large traditional market in Seoul, South Korea. The market is located next to Namdaemun, the "Great South Gate," which was the main southern gate to the old city.Namdaemun Market at It is the oldest and largest market in Korea. History Namdaemun market dates back to 1414, during the reign of , as a government-managed marketplace. In 1608, set up the office o ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
