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Two-way Nondeterministic Finite Automaton
In computer science, in particular in automata theory, a two-way finite automaton is a finite automaton that is allowed to re-read its input. Two-way deterministic finite automaton A two-way deterministic finite automaton (2DFA) is an abstract machine, a generalized version of the deterministic finite automaton (DFA) which can revisit characters already processed. As in a DFA, there are a finite number of states with transitions between them based on the current character, but each transition is also labelled with a value indicating whether the machine will move its position in the input to the left, right, or stay at the same position. Equivalently, 2DFAs can be seen as read-only Turing machines with no work tape, only a read-only input tape. 2DFAs were introduced in a seminal 1959 paper by Rabin and Scott, who proved them to have equivalent power to one-way DFAs. That is, any formal language which can be recognized by a 2DFA can be recognized by a DFA which only examines and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical disciplines (including the design and implementation of Computer architecture, hardware and Computer programming, software). Computer science is generally considered an area of research, academic research and distinct from computer programming. Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing Vulnerability (computing), security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Progr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christos Kapoutsis
{{Disambig ...
Christos may refer to: * Jesus of Nazareth * Christ (title), a title for the Jewish Messiah in Christianity * Christos (surname) * Christos (given name) *, a Greek owned, Liberian flagged cargo ship in service 1962-71 See also * Christ (other) * Christo (other) * Christa (other) * Christus (other) Christus may refer to: * Christ (title) People * Petrus Christus (c. 1410s – c. 1475), Dutch painter * Sir Christus (1978–2017), Finnish musician Music * ''Christus'' (Liszt), an oratorio * ''Christus'' (Mendelssohn), an unfinished orator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Watrous (computer Scientist)
John Harrison Watrous is a professor of computer science at the David R. Cheriton School of Computer Science at the University of Waterloo, a member of the Institute for Quantum Computing, an affiliate member of the Perimeter Institute for Theoretical Physics and a Fellow of the Canadian Institute for Advanced Research.John Watrous at the website. He was a faculty member in the Department of Computer Science at the from 2002 to 2006 where he held a |
Quantum Computing
Quantum computing is a type of computation whose operations can harness the phenomena of quantum mechanics, such as superposition, interference, and entanglement. Devices that perform quantum computations are known as quantum computers. Though current quantum computers may be too small to outperform usual (classical) computers for practical applications, larger realizations are believed to be capable of solving certain computational problems, such as integer factorization (which underlies RSA encryption), substantially faster than classical computers. The study of quantum computing is a subfield of quantum information science. There are several models of quantum computation with the most widely used being quantum circuits. Other models include the quantum Turing machine, quantum annealing, and adiabatic quantum computation. Most models are based on the quantum bit, or "qubit", which is somewhat analogous to the bit in classical computation. A qubit can be in a 1 or 0 quantum s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NL (complexity)
In computational complexity theory, NL (Nondeterministic Logarithmic-space) is the complexity class containing decision problems that can be solved by a nondeterministic Turing machine using a logarithmic amount of memory space. NL is a generalization of L, the class for logspace problems on a deterministic Turing machine. Since any deterministic Turing machine is also a nondeterministic Turing machine, we have that L is contained in NL. NL can be formally defined in terms of the computational resource nondeterministic space (or NSPACE) as NL = NSPACE(log ''n''). Important results in complexity theory allow us to relate this complexity class with other classes, telling us about the relative power of the resources involved. Results in the field of algorithms, on the other hand, tell us which problems can be solved with this resource. Like much of complexity theory, many important questions about NL are still open (see Unsolved problems in computer science). Occasionally NL ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L (complexity)
In computational complexity theory, L (also known as LSPACE or DLOGSPACE) is the complexity class containing decision problems that can be solved by a deterministic Turing machine using a logarithmic amount of writable memory space., Definition 8.12, p. 295., p. 177. Formally, the Turing machine has two tapes, one of which encodes the input and can only be read, whereas the other tape has logarithmic size but can be read as well as written. Logarithmic space is sufficient to hold a constant number of pointers into the input and a logarithmic number of boolean flags, and many basic logspace algorithms use the memory in this way. Complete problems and logical characterization Every non-trivial problem in L is complete under log-space reductions, so weaker reductions are required to identify meaningful notions of L-completeness, the most common being first-order reductions. A 2004 result by Omer Reingold shows that USTCON, the problem of whether there exists a path ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Complexity Theory
In theoretical computer science and mathematics, computational complexity theory focuses on classifying computational problems according to their resource usage, and relating these classes to each other. A computational problem is a task solved by a computer. A computation problem is solvable by mechanical application of mathematical steps, such as an algorithm. A problem is regarded as inherently difficult if its solution requires significant resources, whatever the algorithm used. The theory formalizes this intuition, by introducing mathematical models of computation to study these problems and quantifying their computational complexity, i.e., the amount of resources needed to solve them, such as time and storage. Other measures of complexity are also used, such as the amount of communication (used in communication complexity), the number of gates in a circuit (used in circuit complexity) and the number of processors (used in parallel computing). One of the roles of computationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P Vs
P, or p, is the sixteenth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''pee'' (pronounced ), plural ''pees''. History The Semitic Pê (mouth), as well as the Greek Π or π ( Pi), and the Etruscan and Latin letters that developed from the former alphabet, all symbolized , a voiceless bilabial plosive. Use in writing systems In English orthography and most other European languages, represents the sound . A common digraph in English is , which represents the sound , and can be used to transliterate ''phi'' in loanwords from Greek. In German, the digraph is common, representing a labial affricate . Most English words beginning with are of foreign origin, primarily French, Latin and Greek; these languages preserve Proto-Indo-European initial *p. Native English cognates of such words often start with , since English is a Germanic language and thus ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Sipser
Michael Fredric Sipser (born September 17, 1954) is an American theoretical computer scientist who has made early contributions to computational complexity theory. He is a professor of applied mathematics and was the Dean of Science at the Massachusetts Institute of Technology. Biography Sipser was born and raised in Brooklyn, New York and moved to Oswego, New York when he was 12 years old. He earned his BA in mathematics from Cornell University in 1974 and his PhD in engineering from the University of California at Berkeley in 1980 under the direction of Manuel Blum.Trafton, Anne"Michael Sipser named dean of the School of Science: Sipser has served as interim dean since Marc Kastner’s departure" MIT News Office, June 5, 2014 He joined MIT's Laboratory for Computer Science as a research associate in 1979 and then was a Research Staff Member at IBM Research in San Jose. In 1980, he joined the MIT faculty. He spent the 1985-1986 academic year on the faculty of the Uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viliam Geffert
Viliam Geffert (born 1955) is a Slovak theoretical computer scientist known for his contributions to the computational complexity theory in sublogarithmic space and to the state complexity of two-way finite automata. He has also developed new in-place sorting algorithms. He is a professor and the head of the computer science department at the P. J. Šafárik University in Košice. Biography Geffert did his undergraduate studies at the P. J. Šafárik University, graduating in 1979. He earned his PhD degree in 1988 from the Comenius University Comenius University in Bratislava ( sk, Univerzita Komenského v Bratislave) is the largest university in Slovakia, with most of its faculties located in Bratislava. It was founded in 1919, shortly after the creation of Czechoslovakia. It is name ... in Bratislava. Since 2003, he is a full professor of the P. J. Šafárik University. References External links * {{DEFAULTSORT:Geffert, Viliam Slovak computer scientists Theoret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larry Stockmeyer
Larry Joseph Stockmeyer (1948 – 31 July 2004) was an American computer scientist. He was one of the pioneers in the field of computational complexity theory, and he also worked in the field of distributed computing. He died of pancreatic cancer. Career * 1972: BSc in mathematics, Massachusetts Institute of Technology. * 1972: MSc in electrical engineering, Massachusetts Institute of Technology. * 1974: PhD in computer science, Massachusetts Institute of Technology. ** Supervisor: Albert R. Meyer. * 1974–1982: IBM Research, Thomas J. Watson Research Center, Yorktown Heights, NY. * 1982–November 2003: IBM Research, Almaden Research Center, San Jose, CA. * October 2002–2004: University of California, Santa Cruz, Computer Science Department – Research Associate. Recognition * 1996: Fellow of the Association for Computing Machinery: "For several fundamental contributions to computational complexity theory, which have significantly affected the course of this field. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard J
Richard is a male given name. It originates, via Old French, from Old Frankish and is a compound of the words descending from Proto-Germanic ''*rīk-'' 'ruler, leader, king' and ''*hardu-'' 'strong, brave, hardy', and it therefore means 'strong in rule'. Nicknames include "Richie", "Dick", "Dickon", " Dickie", "Rich", "Rick", "Rico", "Ricky", and more. Richard is a common English, German and French male name. It's also used in many more languages, particularly Germanic, such as Norwegian, Danish, Swedish, Icelandic, and Dutch, as well as other languages including Irish, Scottish, Welsh and Finnish. Richard is cognate with variants of the name in other European languages, such as the Swedish "Rickard", the Catalan "Ricard" and the Italian "Riccardo", among others (see comprehensive variant list below). People named Richard Multiple people with the same name * Richard Andersen (other) * Richard Anderson (other) * Richard Cartwright (other) * Ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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