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Giovanni Pighizzini
Giovanni Pighizzini is an Italian theoretical computer scientist known for his work in formal language theory and particularly in state complexity of two-way finite automata. He earned his PhD in 1993 from the University of Milan, where he is a full professor since 2001. Pighizzini serves as the Steering Committee Chair of the annual Descriptional Complexity of Formal Systems academic conference since 2006. Research contributions Pighizzini obtained optimal state complexity tradeoffs between different types of finite automata over a one-letter alphabet, In particular, in his joint paper with Geffert and Mereghetti he presented the first simulation of two-way nondeterministic finite automata by two-way deterministic finite automata using Savitch's theorem, contributing to the 2DFA vs. 2NFA open question. Jointly with Jirásková, he determined state complexity of self-verifying finite automata. He also contributed to the computational complexity theory In theoretical co ... [...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] |
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] |
Italian Computer Scientists
Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Italian, regional variants of the Italian language ** Languages of Italy, languages and dialects spoken in Italy ** Italian culture, cultural features of Italy ** Italian cuisine, traditional foods ** Folklore of Italy, the folklore and urban legends of Italy ** Mythology of Italy, traditional religion and beliefs Other uses * Italian dressing, a vinaigrette-type salad dressing or marinade * Italian or Italian-A, alternative names for the Ping-Pong virus, an extinct computer virus See also * * * Italia (other) * Italic (other) * Italo (other) * The Italian (other) * Italian people (other) Italian people may refer to: * in terms of ethnicity: all ethnic Italians, in and outside of Italy * in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italian Mathematicians
Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Italian, regional variants of the Italian language ** Languages of Italy, languages and dialects spoken in Italy ** Italian culture, cultural features of Italy ** Italian cuisine, traditional foods ** Folklore of Italy, the folklore and urban legends of Italy ** Mythology of Italy, traditional religion and beliefs Other uses * Italian dressing, a vinaigrette-type salad dressing or marinade * Italian or Italian-A, alternative names for the Ping-Pong virus, an extinct computer virus See also * * * Italia (other) * Italic (other) * Italo (other) * The Italian (other) * Italian people (other) Italian people may refer to: * in terms of ethnicity: all ethnic Italians, in and outside of Italy * in ... [...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] |
Self-verifying Finite Automata
In automata theory, a self-verifying finite automaton (SVFA) is a special kind of a nondeterministic finite automaton (NFA) with a symmetric kind of nondeterminism introduced by Hromkovič and Schnitger. Generally, in self-verifying nondeterminism, each computation path is concluded with any of the three possible answers: ''yes'', ''no'', and ''I do not know''. For each input string, no two paths may give contradictory answers, namely both answers ''yes'' and ''no'' on the same input are not possible. At least one path must give answer ''yes'' or ''no'', and if it is ''yes'' then the string is considered accepted. SVFA accept the same class of languages as deterministic finite automata (DFA) and NFA but have different state complexity. Formal definition An SVFA is represented formally by a 6-tuple, ''A''=(''Q'', Σ, Δ, ''q0'', ''Fa'', ''Fr'') such that (''Q'', Σ, Δ, ''q0'', ''Fa'') is an '' NFA'', and ''Fa'', ''Fr'' are disjoint subsets of ''Q''. For each word ''w = a1a2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Savitch's Theorem
In computational complexity theory, Savitch's theorem, proved by Walter Savitch in 1970, gives a relationship between deterministic and non-deterministic space complexity. It states that for any function f\in\Omega(\log(n)), :\mathsf\left(f\left(n\right)\right) \subseteq \mathsf\left(f\left(n\right)^2\right). In other words, if a nondeterministic Turing machine can solve a problem using f(n) space, a deterministic Turing machine can solve the same problem in the square of that space bound.Arora & Barak (2009) p.86 Although it seems that nondeterminism may produce exponential gains in time (as formalized in the unproven exponential time hypothesis In computational complexity theory, the exponential time hypothesis is an unproven computational hardness assumption that was formulated by . It states that satisfiability of 3-CNF Boolean formulas cannot be solved more quickly than exponential t ...), Savitch's theorem shows that it has a markedly more limited effect on space requ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-way Deterministic 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 ... [...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] |
Formal Language Theory
In logic, mathematics, computer science, and linguistics, a formal language consists of words whose letters are taken from an alphabet and are well-formed according to a specific set of rules. The alphabet of a formal language consists of symbols, letters, or tokens that concatenate into strings of the language. Each string concatenated from symbols of this alphabet is called a word, and the words that belong to a particular formal language are sometimes called ''well-formed words'' or ''well-formed formulas''. A formal language is often defined by means of a formal grammar such as a regular grammar or context-free grammar, which consists of its formation rules. In computer science, formal languages are used among others as the basis for defining the grammar of programming languages and formalized versions of subsets of natural languages in which the words of the language represent concepts that are associated with particular meanings or semantics. In computational complexity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finite Automata
A finite-state machine (FSM) or finite-state automaton (FSA, plural: ''automata''), finite automaton, or simply a state machine, is a mathematical model of computation. It is an abstract machine that can be in exactly one of a finite number of '' states'' at any given time. The FSM can change from one state to another in response to some inputs; the change from one state to another is called a ''transition''. An FSM is defined by a list of its states, its initial state, and the inputs that trigger each transition. Finite-state machines are of two types— deterministic finite-state machines and non-deterministic finite-state machines. A deterministic finite-state machine can be constructed equivalent to any non-deterministic one. The behavior of state machines can be observed in many devices in modern society that perform a predetermined sequence of actions depending on a sequence of events with which they are presented. Simple examples are vending machines, which dispense p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academic Conference
An academic conference or scientific conference (also congress, symposium, workshop, or meeting) is an event for researchers (not necessarily academics) to present and discuss their scholarly work. Together with academic or scientific journals and Preprint archives such as arXiv, conferences provide an important channel for exchange of information between researchers. Further benefits of participating in academic conferences include learning effects in terms of presentation skills and “academic habitus”, receiving feedback from peers for one’s own research, the possibility to engage in informal communication with peers about work opportunities and collaborations, and getting an overview of current research in one or more disciplines. Overview Conferences usually encompass various presentations. They tend to be short and concise, with a time span of about 10 to 30 minutes; presentations are usually followed by a . The work may be bundled in written form as academic pape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
