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Corrado Böhm
Corrado Böhm (17 January 1923 – 23 October 2017) was a Professor Emeritus at the University of Rome "La Sapienza" and a computer scientist known especially for his contributions to the theory of structured programming, constructive mathematics, combinatory logic, lambda calculus, and the semantics and implementation of functional programming languages. Work In his PhD dissertation (in Mathematics, at ETH Zurich, 1951; published in 1954), Böhm describes for the first time a full meta-circular compiler, that is a translation mechanism of a programming language, written in that same language. His most influential contribution is the so-called structured program theorem, published in 1966 together with Giuseppe Jacopini. Together with Alessandro Berarducci, he demonstrated an isomorphism between the strictly-positive algebraic data types and the polymorphic lambda-terms, otherwise known as Böhm–Berarducci encoding. In the lambda calculus, he established an important separat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milan
Milan ( , , Lombard: ; it, Milano ) is a city in northern Italy, capital of Lombardy, and the second-most populous city proper in Italy after Rome. The city proper has a population of about 1.4 million, while its metropolitan city has 3.26 million inhabitants. Its continuously built-up urban area (whose outer suburbs extend well beyond the boundaries of the administrative metropolitan city and even stretch into the nearby country of Switzerland) is the fourth largest in the EU with 5.27 million inhabitants. According to national sources, the population within the wider Milan metropolitan area (also known as Greater Milan), is estimated between 8.2 million and 12.5 million making it by far the largest metropolitan area in Italy and one of the largest in the EU.* * * * Milan is considered a leading alpha global city, with strengths in the fields of art, chemicals, commerce, design, education, entertainment, fashion, finance, healthcar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Böhm's Language
Böhm's language refers to the language, machine and a translation method developed by Corrado Böhm during the latter part of 1950. Böhm used this work as part of his dissertation, submitted in 1951 (amended after submission), published in 1954. The compiler Böhm's work described the first complete meta-circular compiler. The code for the compiler was remarkably precise, and consisted of only 114 lines of code. Since the language accepted only two kinds of expressions: fully parenthesized or without parenthesis, but with operator precedence, therefore the code of the compiler split into two parts. 59 lines were used to handle formulas with parenthesis, 51 to handle operator precedence expressions and 4 to decide between those two cases. Böhm's parsing technique for expressions had only linear complexity. It generated instructions to a structure similar to a binary tree. The language Böhm's language consisted of only assignment operations. It had no special construct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2017 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] |
1923 Births
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album '' Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus. * "Nineteen", a song by Tegan and Sara from the 2007 album '' The Con''. * "XIX" (song), a 2014 song by Slipk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Böhm Tree
In the study of denotational semantics of the lambda calculus, Böhm trees, Lévy-Longo trees, and Berarducci trees are (potentially infinite) tree-like mathematical objects that capture the "meaning" of a term up to some set of "meaningless" terms. Motivation A simple way to read the meaning of a computation is to consider it as a mechanical procedure consisting of a finite number of steps that, when completed, yields a result. In particular, considering the lambda calculus as a rewriting system, each beta reduction step is a rewrite step, and once there are no further beta reductions the term is in normal form. We could thus, naively following Church's suggestion, say the meaning of a term is its normal form, and that terms without a normal form are meaningless. For example the meanings of I = λx.x and I I are both I. This works for any strongly normalizing subset of the lambda calculus, such as a typed lambda calculus. This naive assignment of meaning is however inadequate fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Pioneers In Computer Science
This is a list of people who made transformative breakthroughs in the creation, development and imagining of what computers could do. Pioneers : ''To arrange the list by date or person (ascending or descending), click that column's small "up-down" icon.'' ~ Items marked with a tilde are circa dates. See also * Computer Pioneer Award * IEEE John von Neumann Medal * Grace Murray Hopper Award * History of computing ** History of computing hardware ** History of computing hardware (1960s–present) **History of software * List of computer science awards * List of computer scientists * List of Internet pioneers * List of people considered father or mother of a field § Compume inductees * '' The Man Who Invented the Computer (2010 book) * List of Russian IT developers * List of Women in Technology International Hall of Fame inductees * Timeline of computing * Turing Award * Women in computing Women in computing were among the first programmers in the early 20th century, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structured Program Theorem
The structured program theorem, also called the Böhm–Jacopini theorem, is a result in programming language theory. It states that a class of control-flow graphs (historically called flowcharts in this context) can compute any computable function if it combines subprograms in only three specific ways (control structures). These are #Executing one subprogram, and then another subprogram (sequence) #Executing one of two subprograms according to the value of a boolean expression (selection) #Repeatedly executing a subprogram as long as a boolean expression is true (iteration) The structured chart subject to these constraints may however use additional variables in the form of bits (stored in an extra integer variable in the original proof) in order to keep track of information that the original program represents by the program location. The construction was based on Böhm's programming language P′′. The theorem forms the basis of structured programming, a programming paradigm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turing-complete
In computability theory, a system of data-manipulation rules (such as a computer's instruction set, a programming language, or a cellular automaton) is said to be Turing-complete or computationally universal if it can be used to simulate any Turing machine (devised by English mathematician and computer scientist Alan Turing). This means that this system is able to recognize or decide other data-manipulation rule sets. Turing completeness is used as a way to express the power of such a data-manipulation rule set. Virtually all programming languages today are Turing-complete. A related concept is that of Turing equivalence two computers P and Q are called equivalent if P can simulate Q and Q can simulate P. The Church–Turing thesis conjectures that any function whose values can be computed by an algorithm can be computed by a Turing machine, and therefore that if any real-world computer can simulate a Turing machine, it is Turing equivalent to a Turing machine. A universal Turi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GOTO
GoTo (goto, GOTO, GO TO or other case combinations, depending on the programming language) is a statement found in many computer programming languages. It performs a one-way transfer of control to another line of code; in contrast a function call normally returns control. The jumped-to locations are usually identified using labels, though some languages use line numbers. At the machine code level, a goto is a form of branch or jump statement, in some cases combined with a stack adjustment. Many languages support the goto statement, and many do not (see § language support). The structured program theorem proved that the goto statement is not necessary to write programs that can be expressed as flow charts; some combination of the three programming constructs of sequence, selection/choice, and repetition/iteration are sufficient for any computation that can be performed by a Turing machine, with the caveat that code duplication and additional variables may need to be introduce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P′′
P′′ (P double prime) is a primitive computer programming language created by Corrado BöhmBöhm, C.: "On a family of Turing machines and the related programming language", ICC Bull. 3, 185-194, July 1964.Böhm, C. and Jacopini, G.: "Flow diagrams, Turing machines and languages with only two formation rules", CACM 9(5), 1966. (Note: This is the most-cited paper on the structured program theorem.) in 1964 to describe a family of Turing machines. Definition \mathcal^ (hereinafter written P′′) is formally defined as a set of words on the four-instruction alphabet \, as follows: Syntax # R and \lambda are words in P′′. # If q_1 and q_2 are words in P′′, then q_1 q_2 is a word in P′′. # If q is a word in P′′, then (q) is a word in P′′. # Only words derivable from the previous three rules are words in P′′. Semantics * \ is the tape-alphabet of a Turing machine with left-infinite tape, \Box being the ''blank'' symbol, equivalent to c_0. * All instructions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Association For Theoretical Computer Science
The European Association for Theoretical Computer Science (EATCS) is an international organization with a European focus, founded in 1972. Its aim is to facilitate the exchange of ideas and results among theoretical computer scientists as well as to stimulate cooperation between the theoretical and the practical community in computer science. The major activities of the EATCS are: * Organization of ICALP, the International Colloquium on Automata, Languages and Programming;Brauer, Ute; Brauer, WilfriedEuropean Association for Theoretical Computer Science / About the Association / Silver Jubilee of EATCS/ref> * Publication of the ''Bulletin of the EATCS''; * Publication of a series of monographs and texts on theoretical computer science; * Publication of the journal ''Theoretical Computer Science''; * Publication of the journal ''Fundamenta Informaticae''. EATCS Award Each year, the EATCS Award is awarded in recognition of a distinguished career in theoretical computer science. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contextual Equivalence
Observational equivalence is the property of two or more underlying entities being indistinguishable on the basis of their observable implications. Thus, for example, two scientific theories are observationally equivalent if all of their empirically testable predictions are identical, in which case empirical evidence cannot be used to distinguish which is closer to being correct; indeed, it may be that they are actually two different perspectives on one underlying theory. In econometrics, two parameter values (or two ''structures,'' from among a class of statistical models) are considered observationally equivalent if they both result in the same probability distribution of observable data. This term often arises in relation to the identification problem. In the formal semantics of programming languages, two terms ''M'' and ''N'' are observationally equivalent if and only if, in all contexts ''C'' ..where ''C'' 'M''is a valid term, it is the case that ''C'' 'N''is also a valid ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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