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Horst Schubert
Horst Schubert (11 June 1919 – 2001) was a German mathematician. Schubert was born in Chemnitz and studied mathematics and physics at the Universities of Frankfurt am Main, Zürich and Heidelberg, where in 1948 he received his PhD under Herbert Seifert with thesis ''Die eindeutige Zerlegbarkeit eines Knotens in Primknoten''. From 1948 to 1956 Schubert was an assistant in Heidelberg, where he received in 1952 his habilitation qualification. From 1959 he was a ''professor extraordinarius'' and from 1962 a ''professor ordinarius'' at the University of Kiel. From 1969 to 1984 he was a professor at the University of Düsseldorf. In 1949 he published his proof that every oriented knot in S^3 decomposes as a connect-sum of prime knots in a unique way, up to reordering. After this proof he found a new proof based on his study of incompressible tori in knot complements; he published this work ''Knoten und Vollringe'' in ''Acta Mathematica'', where he defined satellite and companio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemnitz
Chemnitz (; from 1953 to 1990: Karl-Marx-Stadt , ) is the third-largest city in the German state of Saxony after Leipzig and Dresden. It is the 28th largest city of Germany as well as the fourth largest city in the area of former East Germany after (East) Berlin, Leipzig and Dresden. The city is part of the Central German Metropolitan Region, and lies in the middle of a string of cities sitting in the densely populated northern foreland of the Elster and Ore Mountains, stretching from Plauen in the southwest via Zwickau, Chemnitz and Freiberg to Dresden in the northeast. Located in the Ore Mountain Basin, the city is surrounded by the Ore Mountains to the south and the Central Saxon Hill Country to the north. The city stands on the Chemnitz River (progression: ), which is formed through the confluence of the rivers Zwönitz and Würschnitz in the borough of Altchemnitz. The name of the city as well as the names of the rivers are of Slavic origin. Chemnitz is the third larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Der Nachrichtenaufklärung
''General der Nachrichtenaufklärung'' was the signals intelligence agency of the German Army (1935-1945), Heer (German Army), before and during World War II. It was the successor to the former cipher bureau known as Inspectorate 7/VI in operation between 1940 and 1942, when it was further reorganised into the Headquarters for Signal Intelligence (german: Leitstelle der Nachrichtenaufklärung) (abbr. LNA) between 1942 and 1944, until it was finally reorganised in October 1944 into the GdNA. The agency was also known at the OKH/Gend Na, GendNa or Inspectorate 7 or more commonly OKH/GdNA. ''Inspectorate 7/VI'' was also known as In 7 or In/7 or In 7/VI and also OKH/Chi. Chi-Stelle From ''Chiffrierabteilung'' (English: "cipher department"). ''Chi-Stelle'', translates to "Cipher Department Location". Background Key personnel Senior personnel General der Nachrichtentruppe Erich Fellgiebel, was Director of the Code and Cipher section of the Defense Ministry from 1931 to 1932 and h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2001 Deaths
This is a list of deaths of notable people, organised by year. New deaths articles are added to their respective month (e.g., Deaths in ) and then linked here. 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 See also * Lists of deaths by day The following pages, corresponding to the Gregorian calendar, list the historical events, births, deaths, and holidays and observances of the specified day of the year: Footnotes See also * Leap year * List of calendars * List of non-standard ... * Deaths by year {{DEFAULTSORT:deaths by year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1919 Births
Events January * January 1 ** The Czechoslovak Legions occupy much of the self-proclaimed "free city" of Pressburg (now Bratislava), enforcing its incorporation into the new republic of Czechoslovakia. ** HMY ''Iolaire'' sinks off the coast of the Hebrides; 201 people, mostly servicemen returning home to Lewis and Harris, are killed. * January 2– 22 – Russian Civil War: The Red Army's Caspian-Caucasian Front begins the Northern Caucasus Operation against the White Army, but fails to make progress. * January 3 – The Faisal–Weizmann Agreement is signed by Emir Faisal (representing the Arab Kingdom of Hejaz) and Zionist leader Chaim Weizmann, for Arab–Jewish cooperation in the development of a Jewish homeland in Palestine, and an Arab nation in a large part of the Middle East. * January 5 – In Germany: ** Spartacist uprising in Berlin: The Marxist Spartacus League, with the newly formed Communist Party of Germany and the Independent Social De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Knot
In the mathematical theory of knots, a satellite knot is a knot that contains an incompressible, non boundary-parallel torus in its complement. Every knot is either hyperbolic, a torus, or a satellite knot. The class of satellite knots include composite knots, cable knots, and Whitehead doubles. A satellite ''link'' is one that orbits a companion knot ''K'' in the sense that it lies inside a regular neighborhood of the companion. A satellite knot K can be picturesquely described as follows: start by taking a nontrivial knot K' lying inside an unknotted solid torus V. Here "nontrivial" means that the knot K' is not allowed to sit inside of a 3-ball in V and K' is not allowed to be isotopic to the central core curve of the solid torus. Then tie up the solid torus into a nontrivial knot. This means there is a non-trivial embedding f\colon V \to S^3 and K = f\left(K'\right). The central core curve of the solid torus V is sent to a knot H, which is called the "companion knot" a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Lieutenant
First lieutenant is a commissioned officer military rank in many armed forces; in some forces, it is an appointment. The rank of lieutenant has different meanings in different military formations, but in most forces it is sub-divided into a senior (first lieutenant) and junior (second lieutenant) rank. The NATO equivalent rank for land force officers is OF-1 rank. In navies, while certain rank insignia may carry the name lieutenant, the term may also be used to relate to a particular post or duty, rather than a rank. Indonesia In Indonesia, "first lieutenant" is known as ''Letnan Satu'' (''Lettu''), Indonesian National Armed Forces uses this rank across all three of its services. It is just above the rank of second lieutenant and just below the rank of captain. Israel In the Israel Defense Forces, the rank above second lieutenant is simply lieutenant. The rank of (קצין מקצועי אקדמאי (קמ"א (''katsín miktsoí akademai'' or "kama"), a professional aca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code
In communications and information processing, code is a system of rules to convert information—such as a letter, word, sound, image, or gesture—into another form, sometimes shortened or secret, for communication through a communication channel or storage in a storage medium. An early example is an invention of language, which enabled a person, through speech, to communicate what they thought, saw, heard, or felt to others. But speech limits the range of communication to the distance a voice can carry and limits the audience to those present when the speech is uttered. The invention of writing, which converted spoken language into visual symbols, extended the range of communication across space and time. The process of encoding converts information from a source into symbols for communication or storage. Decoding is the reverse process, converting code symbols back into a form that the recipient understands, such as English or/and Spanish. One reason for coding is to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cipher
In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is ''encipherment''. To encipher or encode is to convert information into cipher or code. In common parlance, "cipher" is synonymous with "code", as they are both a set of steps that encrypt a message; however, the concepts are distinct in cryptography, especially classical cryptography. Codes generally substitute different length strings of characters in the output, while ciphers generally substitute the same number of characters as are input. There are exceptions and some cipher systems may use slightly more, or fewer, characters when output versus the number that were input. Codes operated by substituting according to a large codebook which linked a random string of characters or numbers to a word or phrase. For example, "UQJHSE" could be the code for "Proceed to the following ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polish Land Forces
The Land Forces () are the land forces of the Polish Armed Forces. They currently contain some 62,000 active personnel and form many components of the European Union and NATO deployments around the world. Poland's recorded military history stretches back a millennium – since the 10th century (see List of Polish wars and History of the Polish Army). Poland's modern army was formed after Poland regained independence following World War I in 1918. History 1918–1938 When Poland regained independence in 1918, it recreated its military which participated in the Polish–Soviet War of 1919–1921, and in the two smaller conflicts ( Polish–Ukrainian War (1918–1919) and the Polish–Lithuanian War (1920)). Initially, right after the First World War, Poland had five military districts (1918–1921): * Poznań Military District (Poznański Okręg Wojskowy), HQ in Poznań * Kraków Military District (Krakowski Okręg Wojskowy), HQ in Kraków * Łódź Military District (Łód ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Army
The Workers' and Peasants' Red Army (Russian: Рабо́че-крестья́нская Кра́сная армия),) often shortened to the Red Army, was the army and air force of the Russian Soviet Federative Socialist Republic and, after 1922, the Union of Soviet Socialist Republics. The army was established in January 1918. The Bolsheviks raised an army to oppose the military confederations (especially the various groups collectively known as the White Army) of their adversaries during the Russian Civil War. Starting in February 1946, the Red Army, along with the Soviet Navy, embodied the main component of the Soviet Armed Forces; taking the official name of "Soviet Army", until its dissolution in 1991. The Red Army provided the largest land force in the Allied victory in the European theatre of World War II, and its invasion of Manchuria assisted the unconditional surrender of Imperial Japan. During operations on the Eastern Front, it accounted for 75–80% of casual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signals Intelligence
Signals intelligence (SIGINT) is intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication (electronic intelligence—abbreviated to ELINT). Signals intelligence is a subset of intelligence collection management. As classified and sensitive information is usually encrypted, signals intelligence in turn involves the use of cryptanalysis to decipher the messages. Traffic analysis—the study of who is signaling whom and in what quantity—is also used to integrate information again. History Origins Electronic interceptions appeared as early as 1900, during the Boer War of 1899–1902. The British Royal Navy had installed wireless sets produced by Marconi on board their ships in the late 1890s, and the British Army used some limited wireless signalling. The Boers captured some wireless sets and used them to make vital transmis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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