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Henry Perigal
Henry Perigal, Jr. Royal Astronomical Society, FRAS Royal Institution, MRI (1 April 1801 – 6 June 1898) was a British stockbroker and amateur mathematician, known for his dissection problem, dissection-based proof of the Pythagorean theorem and for his unorthodox belief that the moon does not rotate...... Biography Perigal descended from a Huguenot family who emigrated to England in the late 17th century, and was the oldest of six siblings. After working as a clerk for the Privy Council of the United Kingdom, Privy Council, he became a bookkeeper in a London stockbrokerage in the 1840s. He remained a lifelong bachelor. Perigal was a member of the London Mathematical Society from 1868 to 1897, and was treasurer of the Royal Meteorological Society for 45 years, from 1853 until his death in 1898. He was elected as a fellow of the Royal Astronomical Society in 1850. He attended the Royal Institution regularly as a visitor for many years, and finally became a member in 1895, at age ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics with the major subdisciplines of number theory, algebra, geometry, and analysis, respectively. There is no general consensus among mathematicians about a common definition for their academic discipline. Most mathematical activity involves the discovery of properties of abstract objects and the use of pure reason to prove them. These objects consist of either abstractions from nature orin modern mathematicsentities that are stipulated to have certain properties, called axioms. A ''proof'' consists of a succession of applications of deductive rules to already established results. These results include previously proved theorems, axioms, andin case of abstraction from naturesome basic properties that are considered true starting points of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometric Dissections And Transpositions
Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is called a ''geometer''. Until the 19th century, geometry was almost exclusively devoted to Euclidean geometry, which includes the notions of point, line, plane, distance, angle, surface, and curve, as fundamental concepts. During the 19th century several discoveries enlarged dramatically the scope of geometry. One of the oldest such discoveries is Carl Friedrich Gauss' ("remarkable theorem") that asserts roughly that the Gaussian curvature of a surface is independent from any specific embedding in a Euclidean space. This implies that surfaces can be studied ''intrinsically'', that is, as stand-alone spaces, and has been expanded into the theory of manifolds and Riemannian geometry. Later in the 19th century, it appeared that geometries wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1801 Births
Eighteen or 18 may refer to: * 18 (number), the natural number following 17 and preceding 19 * one of the years 18 BC, AD 18, 1918, 2018 Film, television and entertainment * ''18'' (film), a 1993 Taiwanese experimental film based on the short story ''God's Dice'' * ''Eighteen'' (film), a 2005 Canadian dramatic feature film * 18 (British Board of Film Classification), a film rating in the United Kingdom, also used in Ireland by the Irish Film Classification Office * 18 (''Dragon Ball''), a character in the ''Dragon Ball'' franchise * "Eighteen", a 2006 episode of the animated television series ''12 oz. Mouse'' Music Albums * ''18'' (Moby album), 2002 * ''18'' (Nana Kitade album), 2005 * '' 18...'', 2009 debut album by G.E.M. Songs * "18" (5 Seconds of Summer song), from their 2014 eponymous debut album * "18" (One Direction song), from their 2014 studio album ''Four'' * "18", by Anarbor from their 2013 studio album '' Burnout'' * "I'm Eighteen", by Alice Cooper common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lathe
A lathe () is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis. Lathes are used in woodturning, metalworking, metal spinning, thermal spraying, parts reclamation, and glass-working. Lathes can be used to shape pottery, the best-known design being the Potter's wheel. Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The workpiece is usually held in place by either one or two ''centers'', at least one of which can typically be moved horizontally to accommodate varying workpiece lengths. Other work-holding methods include clamping the work about the axis of rotation using a chuck or col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Trisection
In geometry, a square trisection is a type of dissection problem which consists of cutting a square into pieces that can be rearranged to form three identical squares. History The dissection of a square in three congruent partitions is a geometrical problem that dates back to the Islamic Golden Age. Craftsman who mastered the art of zellige needed innovative techniques to achieve their fabulous mosaics with complex geometric figures. The first solution to this problem was proposed in the 10th century AD by the Persian mathematician Abu'l-Wafa' (940-998) in his treatise ''"On the geometric constructions necessary for the artisan"''. Abu'l-Wafa' also used his dissection to demonstrate the Pythagorean theorem. This geometrical proof of Pythagoras' theorem would be rediscovered in the years 1835 - 1840 by Henry Perigal and published in 1875. Search of optimality The beauty of a dissection depends on several parameters. However, it is usual to search for solutions with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miklós Laczkovich
Miklós Laczkovich (born 21 February 1948) is a Hungarian mathematician mainly noted for his work on real analysis and geometric measure theory. His most famous result is the solution of Tarski's circle-squaring problem in 1989.Ruthen, R. (1989) ''Squaring the Circle'', Scientific American 261(1), 22-24. Career Laczkovich received his degree in mathematics in 1971 at Eötvös Loránd University, where he has been teaching ever since, currently leading the Department of Analysis. He was also a professor at University College London, where he is now a professor emeritus. He became corresponding member (1993), then member (1998) of the Hungarian Academy of Sciences. He has held several guest professor positions in the UK, Canada, Italy and the United States. Also being a prolific author, he published over 100 papers and two books, one of which, ''Conjecture and Proof'', was an international success. One of his results is the solution of the Kemperman problem: if ''f'' is a real f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Israel Journal Of Mathematics
'' Israel Journal of Mathematics'' is a peer-reviewed mathematics journal published by the Hebrew University of Jerusalem (Magnes Press). Founded in 1963, as a continuation of the ''Bulletin of the Research Council of Israel'' (Section F), the journal publishes articles on all areas of mathematics. The journal is indexed by ''Mathematical Reviews'' and Zentralblatt MATH. Its 2009 MCQ was 0.70, and its 2009 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... was 0.754. External links * Mathematics journals Publications established in 1963 English-language journals Bimonthly journals Hebrew University of Jerusalem {{math-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarski's Circle-squaring Problem
Tarski's circle-squaring problem is the challenge, posed by Alfred Tarski in 1925, to take a disc in the plane, cut it into finitely many pieces, and reassemble the pieces so as to get a square of equal area. This was proven to be possible by Miklós Laczkovich in 1990; the decomposition makes heavy use of the axiom of choice and is therefore non-constructive. Laczkovich estimated the number of pieces in his decomposition at roughly 1050. A constructive solution was given by Łukasz Grabowski, András Máthé and Oleg Pikhurko in 2016 which worked everywhere except for a set of measure zero. More recently, gave a completely constructive solution using about 10^ Borel pieces. In 2021 Máthé, Noel and Pikhurko improved the properties of the pieces. In particular, Lester Dubins, Morris W. Hirsch & Jack Karush proved it is impossible to dissect a circle and make a square using pieces that could be cut with an idealized pair of scissors (that is, having Jordan curve boundary). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London Borough Of Havering
The London Borough of Havering () in East London, England, forms part of Outer London. It has a population of 259,552 inhabitants; the principal town is Romford, while other communities are Hornchurch, Upminster, Collier Row and Rainham. The borough is mainly suburban, with large areas of protected open space. Romford is a major retail and night time entertainment centre, and to the south the borough extends into the London Riverside redevelopment area of the Thames Gateway. The name Havering is a reference to the Royal Liberty of Havering which occupied the area for several centuries. The local authority is Havering London Borough Council. It is the easternmost London borough. Population In 2011, the borough had a population of 237,232 over . Havering has a lower population density than other London Boroughs as large areas are parkland and (more than half the borough) is Metropolitan Green Belt protected land. Those areas of development are extensive but rarely intensive. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Essex
Essex () is a county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the River Thames to the south, and Greater London to the south and south-west. There are three cities in Essex: Southend, Colchester and Chelmsford, in order of population. For the purposes of government statistics, Essex is placed in the East of England region. There are four definitions of the extent of Essex, the widest being the ancient county. Next, the largest is the former postal county, followed by the ceremonial county, with the smallest being the administrative county—the area administered by the County Council, which excludes the two unitary authorities of Thurrock and Southend-on-Sea. The ceremonial county occupies the eastern part of what was, during the Early Middle Ages, the Anglo-Saxon Kingdom of Essex. As well as rural areas and urban areas, it forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wennington, London
Wennington is a small village in the London Borough of Havering, in east London. It is situated 14.8 miles (23.8 km) east of Charing Cross. Wennington was an ancient parish in the county of Essex that was abolished for civil purposes in 1934. It is peripheral to London, forming a ribbon development extending from the eastern edge of the urban sprawl and surrounded by the Metropolitan Green Belt. Wennington was added to Hornchurch Urban District in 1934 and has formed part of Greater London since 1965. History Wennington is recorded in the Domesday Book of 1086 as ''Wemtuna''. The manor had only three households and was in the possession of Westminster Abbey. The Church of England parish church, St Mary and St Peter's, dates from the 12th century. The parish included the Thameside area of Coldharbour, the Wennington Marshes and the village of Wennington. The Wennington parish became part of the Romford Poor Law Union in 1836. It was the smallest parish in the union with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
