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Alan Selman
Alan Louis Selman (April 2, 1941 – January 22, 2021) was a mathematician and theoretical computer scientist known for his research on structural complexity theory, the study of computational complexity in terms of the relation between complexity classes rather than individual algorithmic problems. Education and career Selman was a graduate of the City College of New York. He earned a master's degree at the University of California, Berkeley before completing his Ph.D. in 1970 at Pennsylvania State University. His dissertation, ''Arithmetical Reducibilities and Sets of Formulas Valid in Finite Structures'', was supervised by Paul Axt, a student of Stephen Cole Kleene. He became a postdoctoral researcher at Carnegie Mellon University, and an assistant professor of mathematics at Florida State University, before moving to the computer science department of Iowa State University, eventually becoming a full professor there. In the late 1980s he moved to Northeastern Universit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New York City, NY
New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the United States, and is more than twice as populous as second-place Los Angeles. New York City lies at the southern tip of New York State, and constitutes the geographical and demographic center of both the Northeast megalopolis and the New York metropolitan area, the largest metropolitan area in the world by urban landmass. With over 20.1 million people in its metropolitan statistical area and 23.5 million in its combined statistical area as of 2020, New York is one of the world's most populous megacities, and over 58 million people live within of the city. New York City is a global cultural, financial, entertainment, and media center with a significant influence on commerce, health care and life sciences, research, technology, educati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theoretical Computer Science
Theoretical computer science (TCS) is a subset of general computer science and mathematics that focuses on mathematical aspects of computer science such as the theory of computation, lambda calculus, and type theory. It is difficult to circumscribe the theoretical areas precisely. The Association for Computing Machinery, ACM's ACM SIGACT, Special Interest Group on Algorithms and Computation Theory (SIGACT) provides the following description: History While logical inference and mathematical proof had existed previously, in 1931 Kurt Gödel proved with his incompleteness theorem that there are fundamental limitations on what statements could be proved or disproved. Information theory was added to the field with a 1948 mathematical theory of communication by Claude Shannon. In the same decade, Donald Hebb introduced a mathematical model of Hebbian learning, learning in the brain. With mounting biological data supporting this hypothesis with some modification, the fields of n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unambiguous Turing Machine
In theoretical computer science, a Turing machine is a theoretical machine that is used in thought experiments to examine the abilities and limitations of computers. An unambiguous Turing machine is a special kind of non-deterministic Turing machine, which, in some sense, is similar to a deterministic Turing machine. Formal definition A ''non-deterministic Turing machine'' is represented formally by a 6-tuple, M=(Q, \Sigma, \iota, \sqcup, A, \delta), as explained in the page ''non-deterministic Turing machine In theoretical computer science, a nondeterministic Turing machine (NTM) is a theoretical model of computation whose governing rules specify more than one possible action when in some given situations. That is, an NTM's next state is ''not'' comp ...''. An ''unambiguous Turing machine'' is a non-deterministic Turing machine such that, for every input w=a_1,a_2,...,a_n, there exists at most one sequence of configurations c_0,c_1,...,c_m with the following conditions: # c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UP (complexity)
In complexity theory, UP (unambiguous non-deterministic polynomial-time) is the complexity class of decision problems solvable in polynomial time on an unambiguous Turing machine with at most one accepting path for each input. UP contains P and is contained in NP. A common reformulation of NP states that a language is in NP if and only if a given answer can be verified by a deterministic machine in polynomial time. Similarly, a language is in UP if a given answer can be verified in polynomial time, and the verifier machine only accepts at most ''one'' answer for each problem instance. More formally, a language ''L'' belongs to UP if there exists a two-input polynomial-time algorithm ''A'' and a constant ''c'' such that :if x in ''L'' , then there exists a unique certificate ''y'' with , y, = O(, x, ^c) such that :if x is not in ''L'', there is no certificate ''y'' with , y, = O(, x, ^c) such that :algorithm ''A'' verifies ''L'' in polynomial time. UP (and its complement co- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promise Problem
In computational complexity theory, a promise problem is a generalization of a decision problem where the input is promised to belong to a particular subset of all possible inputs. Unlike decision problems, the ''yes'' instances (the inputs for which an algorithm must return ''yes'') and ''no'' instances do not exhaust the set of all inputs. Intuitively, the algorithm has been ''promised'' that the input does indeed belong to set of ''yes'' instances or ''no'' instances. There may be inputs which are neither ''yes'' nor ''no''. If such an input is given to an algorithm for solving a promise problem, the algorithm is allowed to output anything, and may even not halt. Formal definition A decision problem can be associated with a language L \subseteq \^*, where the problem is to accept all inputs in L and reject all inputs not in L. For a promise problem, there are two languages, L_ and L_, which must be disjoint, which means L_ \cap L_ = \varnothing, such that all the inputs in L_ a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduction (complexity)
In computability theory and computational complexity theory, a reduction is an algorithm for transforming one problem into another problem. A sufficiently efficient reduction from one problem to another may be used to show that the second problem is at least as difficult as the first. Intuitively, problem ''A'' is reducible to problem ''B'', if an algorithm for solving problem ''B'' efficiently (if it existed) could also be used as a subroutine to solve problem ''A'' efficiently. When this is true, solving ''A'' cannot be harder than solving ''B''. "Harder" means having a higher estimate of the required computational resources in a given context (e.g., higher time complexity, greater memory requirement, expensive need for extra hardware processor cores for a parallel solution compared to a single-threaded solution, etc.). The existence of a reduction from ''A'' to ''B'', can be written in the shorthand notation ''A'' ≤m ''B'', usually with a subscript on the ≤ to indicate the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theory Of Computing Systems
''Theory of Computing Systems'' is a peer-reviewed scientific journal published by Springer Verlag. Published since 1967 as ''Mathematical Systems Theory'' and since volume 30 in 1997 under its current title, it is devoted to publishing original research from all areas of theoretical computer science, such as computational complexity, algorithms and data structures, or parallel and distributed algorithms and architectures. It is published 8 times per year since 2018, although the frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ... varied in the past. References External links * Computer science journals Theoretical computer science Springer Science+Business Media academic journals 8 times per year journals {{Computer-science-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Complexity Conference
The Computational Complexity Conference (CCC), is an academic conference in the field of theoretical computer science whose roots date to 1986. It fosters research in computational complexity theory, and is typically held annually between mid-May and mid-July in North America or Europe. As of 2015, CCC is organized independently by thComputational Complexity Foundation (CCF) History CCC was first organized in 1986 under the name "Structure in Complexity Theory Conference" (Structures) with support from the US National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National I .... The conference was sponsored by thIEEE Computer Society Technical Committee on Mathematical Foundations of Computingfrom 1987-2014. In 1996, the conference was renamed the "Annual IEEE Conference on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northeastern University
Northeastern University (NU) is a private university, private research university with its main campus in Boston. Established in 1898, the university offers undergraduate and graduate programs on its main campus as well as satellite campuses in Charlotte, North Carolina; Seattle, Washington; San Jose, California; Oakland, California; Portland, Maine; and Toronto and Vancouver in Canada. In 2019, Northeastern purchased the New College of the Humanities in London, England. The university's enrollment is approximately 19,000 undergraduate students and 8,600 graduate students. It is Carnegie Classification of Institutions of Higher Education, classified among List of research universities in the United States, "R1: Doctoral Universities – Very high research activity". Northeastern faculty and alumni include Nobel Prize laureates, Rhodes, Truman, Marshall, and Churchill scholars. Undergraduate admission to the university is categorized as "most selective." Northeastern features a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iowa State University
Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the nation's first designated land-grant institution when the Iowa Legislature accepted the provisions of the 1862 Morrill Act on September 11, 1862, making Iowa the first state in the nation to do so. On July 4, 1959, the college was officially renamed Iowa State University of Science and Technology. Iowa State is classified among "R1: Doctoral Universities – Very high research activity". The university is home to the Ames Laboratory, one of ten national U.S. Department of Energy Office of Science research laboratories, the Biorenewables Research Laboratory, the Plant Sciences Institute, and various other research institutes. Iowa State is the second-largest university in the State of Iowa by undergraduate enrollment. The university's ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florida State University
Florida State University (FSU) is a public research university in Tallahassee, Florida. It is a senior member of the State University System of Florida. Founded in 1851, it is located on the oldest continuous site of higher education in the state of Florida. Florida State University comprises 16 separate colleges and more than 110 centers, facilities, labs and institutes that offer more than 360 programs of study, including professional school programs. In 2021, the university enrolled 45,493 students from all 50 states and 130 countries. Florida State is home to Florida's only national laboratory, the National High Magnetic Field Laboratory, and is the birthplace of the commercially viable anti-cancer drug Taxol. Florida State University also operates the John & Mable Ringling Museum of Art, the State Art Museum of Florida and one of the largest museum/university complexes in the nation. The university is accredited by the Southern Association of Colleges and Schools (SACS). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnegie Mellon University
Carnegie Mellon University (CMU) is a private research university in Pittsburgh, Pennsylvania. One of its predecessors was established in 1900 by Andrew Carnegie as the Carnegie Technical Schools; it became the Carnegie Institute of Technology in 1912 and began granting four-year degrees in the same year. In 1967, the Carnegie Institute of Technology merged with the Mellon Institute of Industrial Research, founded in 1913 by Andrew Mellon and Richard B. Mellon and formerly a part of the University of Pittsburgh. Carnegie Mellon University has operated as a single institution since the merger. The university consists of seven colleges and independent schools: The College of Engineering, College of Fine Arts, Dietrich College of Humanities and Social Sciences, Mellon College of Science, Tepper School of Business, Heinz College of Information Systems and Public Policy, and the School of Computer Science. The university has its main campus located 5 miles (8 km) from Downto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
