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Ehrenfeucht–Fraïssé Game
In the mathematical discipline of model theory, the Ehrenfeucht–Fraïssé game (also called back-and-forth games) is a technique based on game semantics for determining whether two structures are elementarily equivalent. The main application of Ehrenfeucht–Fraïssé games is in proving the inexpressibility of certain properties in first-order logic. Indeed, Ehrenfeucht–Fraïssé games provide a complete methodology for proving inexpressibility results for first-order logic. In this role, these games are of particular importance in finite model theory and its applications in computer science (specifically computer aided verification and database theory), since Ehrenfeucht–Fraïssé games are one of the few techniques from model theory that remain valid in the context of finite models. Other widely used techniques for proving inexpressibility results, such as the compactness theorem, do not work in finite models. Ehrenfeucht–Fraïssé-like games can also be defined for oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematics
Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many areas of mathematics, which include number theory (the study of numbers), algebra (the study of formulas and related structures), geometry (the study of shapes and spaces that contain them), Mathematical analysis, analysis (the study of continuous changes), and set theory (presently used as a foundation for all mathematics). Mathematics involves the description and manipulation of mathematical object, abstract objects that consist of either abstraction (mathematics), abstractions from nature orin modern mathematicspurely abstract entities that are stipulated to have certain properties, called axioms. Mathematics uses pure reason to proof (mathematics), prove properties of objects, a ''proof'' consisting of a succession of applications of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sentence (mathematical Logic)
In mathematical logic, a sentence (or closed formula)Edgar Morscher, "Logical Truth and Logical Form", ''Grazer Philosophische Studien'' 82(1), pp. 77–90. of a predicate logic is a Boolean-valued well-formed formula with no free variables. A sentence can be viewed as expressing a proposition, something that ''must'' be true or false. The restriction of having no free variables is needed to make sure that sentences can have concrete, fixed truth values: as the free variables of a (general) formula can range over several values, the truth value of such a formula may vary. Sentences without any logical connectives or quantifiers in them are known as atomic sentences; by analogy to atomic formula. Sentences are then built up out of atomic sentences by applying connectives and quantifiers. A set of sentences is called a theory; thus, individual sentences may be called theorems. To properly evaluate the truth (or falsehood) of a sentence, one must make reference to an interpr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Ordering
In mathematics, a total order or linear order is a partial order in which any two elements are comparable. That is, a total order is a binary relation \leq on some set X, which satisfies the following for all a, b and c in X: # a \leq a ( reflexive). # If a \leq b and b \leq c then a \leq c ( transitive). # If a \leq b and b \leq a then a = b ( antisymmetric). # a \leq b or b \leq a (strongly connected, formerly called totality). Requirements 1. to 3. just make up the definition of a partial order. Reflexivity (1.) already follows from strong connectedness (4.), but is required explicitly by many authors nevertheless, to indicate the kinship to partial orders. Total orders are sometimes also called simple, connex, or full orders. A set equipped with a total order is a totally ordered set; the terms simply ordered set, linearly ordered set, toset and loset are also used. The term ''chain'' is sometimes defined as a synonym of ''totally ordered set'', but generally refers to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bruno Poizat
Bruno may refer to: People and fictional characters * Bruno (name), including lists of people and fictional characters with either the given name or surname * Bruno, Duke of Saxony (died 880) * Bruno the Great (925–965), Archbishop of Cologne, Duke of Lotharingia and saint * Bruno (bishop of Verden) (920–976), German Roman Catholic bishop * Pope Gregory V (c. 972–999), born Bruno of Carinthia * Bruno of Querfurt (c. 974–1009), Christian missionary bishop, martyr and saint * Bruno of Augsburg (c. 992–1029), Bishop of Augsburg * Bruno (bishop of Würzburg) (1005–1045), German Roman Catholic bishop * Pope Leo IX (1002–1054), born Bruno of Egisheim-Dagsburg * Bruno II (1024–1057), Frisian count or margrave * Bruno the Saxon (fl. 2nd half of the 11th century), historian * Saint Bruno of Cologne (d. 1101), founder of the Carthusians * Bruno (bishop of Segni) (c. 1045–1123), Italian Roman Catholic bishop and saint * Bruno (archbishop of Trier) (died 1124), Germa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilfrid Hodges
Wilfrid Augustine Hodges, Fellow of the British Academy, FBA (born 27 May 1941) is a British mathematician and logic, logician known for his work in model theory. Life Hodges attended New College, Oxford (1959–65), where he received degrees in both ''Literae Humaniores'' and (Christianic) Theology. In 1970 he was awarded a doctorate for a thesis in Logic. He lectured in both Philosophy and Mathematics at Bedford College (London), Bedford College, University of London. He has held visiting appointments in the department of philosophy at the University of California and in the department of mathematics at University of Colorado at Boulder, University of Colorado. Hodges was Professor of Mathematics at Queen Mary College, University of London from 1987 to 2006 and is the author of books on logic. Honors and awards Hodges was President of the British Logic Colloquium, of the European Association for Logic, Language and Information and of the Division of Logic, Methodology, and Phi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heloise And Abelard
Héloïse; c. 1100–01? – 16 May 1163–64?), variously Héloïse d'ArgenteuilCharrier, Charlotte. Heloise Dans L'histoire Et Dans la Legende. Librairie Ancienne Honore Champion Quai Malaquais, VI, Paris, 1933 or Héloïse du Paraclet, was a French nun, philosopher, writer, scholar, and abbess. Héloïse was a renowned "woman of letters" and philosopher of love and friendship, as well as an eventual high ranking abbess in the Catholic Church. She achieved approximately the level and political power of a bishop in 1147 when she was granted the rank of prelate nullius. She is famous in history and popular culture for her love affair and correspondence with the leading medieval logician and theologian Peter Abelard, who became her colleague, collaborator, and husband. She is known for exerting critical intellectual influence upon his work and posing many challenging questions to him such as those in the ''Problemata Heloissae''. Her surviving letters are considered a foundat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joel Spencer
Joel Spencer (born April 20, 1946) is an American mathematician. He is a combinatorialist who has worked on probabilistic methods in combinatorics and on Ramsey theory. He received his doctorate from Harvard University in 1970, under the supervision of Andrew Gleason. He is currently () a professor at the Courant Institute of Mathematical Sciences of New York University. Spencer's work was heavily influenced by Paul Erdős, with whom he coauthored many papers (giving him an Erdős number of 1). In 1963, while studying at the Massachusetts Institute of Technology, Spencer became a Putnam Fellow. In 1984, Spencer received a Lester R. Ford Award. He was an Erdős Lecturer at Hebrew University of Jerusalem in 2001. In 2012, he became a fellow of the American Mathematical Society. He was elected as a fellow of the Society for Industrial and Applied Mathematics in 2017, "for contributions to discrete mathematics and theory of computing, particularly random graphs and networks, Ramsey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andrzej Ehrenfeucht
Andrzej Ehrenfeucht (, born 8 August 1932) is a Polish-American mathematician and computer scientist. Life Andrzej Ehrenfeucht formulated the Ehrenfeucht–Fraïssé game, using the back-and-forth method given in Roland Fraïssé's PhD thesis. Also named for Ehrenfeucht is the Ehrenfeucht–Mycielski sequence. In 1971 Ehrenfeucht was a founding member of the Department of Computer Science at the University of Colorado at Boulder. He currently teaches and does research at the University, where he runs a project, "breaking away", with Patricia Baggett; the project, using hands-on activities, aims at raising high-school students' interest in mathematics and technology. Two of Ehrenfeucht's students, Eugene Myers and David Haussler, contributed to the sequencing of the human genome. They, with Harold Gabow, Ross McConnell, and Grzegorz Rozenberg, spoke at a 2012 University of Colorado two-day symposium honoring Ehrenfeucht's 80th birthday. Two journal issues have come out in h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roland Fraïssé
Roland Fraïssé (; 12 March 1920 – 30 March 2008) was a French mathematical logician. Life Fraïssé received his doctoral degree from the University of Paris in 1953. In his thesis, Fraïssé used the back-and-forth method to determine whether two model-theoretic structures were elementarily equivalent. This method of determining elementary equivalence was later formulated as the Ehrenfeucht–Fraïssé game. Fraïssé worked primarily in relation theory. Another of his important works was the Fraïssé construction of a Fraïssé limit of finite structures. He also formulated Fraïssé's conjecture on order embeddings, and introduced the notion of compensor in the theory of posets.Petits posets : dénombrement, représentabilité par cercles et compenseurs, Roland Fraïssé and Nik Lygeros, ''Comptes Rendus de l'Académie des Sciences'', Série I 313 (1991), no. 7, 417–420 Most of his career was spent as Professor at the University of Provence in Marseille ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Back-and-forth Method
In mathematical logic, especially set theory and model theory, the back-and-forth method is a method for showing isomorphism between countably infinite structures satisfying specified conditions. In particular it can be used to prove that * any two countably infinite densely ordered sets (i.e., linearly ordered in such a way that between any two members there is another) without endpoints are isomorphic. An isomorphism between linear orders is simply a strictly increasing bijection. This result implies, for example, that there exists a strictly increasing bijection between the set of all rational numbers and the set of all real algebraic numbers. * any two countably infinite atomless Boolean algebras are isomorphic to each other. * any two equivalent countable atomic models of a theory are isomorphic. * the Erdős–Rényi model of random graphs, when applied to countably infinite graphs, almost surely produces a unique graph, the Rado graph. * any two many-complete recursively ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive integers Some authors acknowledge both definitions whenever convenient. Sometimes, the whole numbers are the natural numbers as well as zero. In other cases, the ''whole numbers'' refer to all of the integers, including negative integers. The counting numbers are another term for the natural numbers, particularly in primary education, and are ambiguous as well although typically start at 1. The natural numbers are used for counting things, like "there are ''six'' coins on the table", in which case they are called ''cardinal numbers''. They are also used to put things in order, like "this is the ''third'' largest city in the country", which are called ''ordinal numbers''. Natural numbers are also used as labels, like Number (sports), jersey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relation (mathematics)
In mathematics, a relation denotes some kind of ''relationship'' between two mathematical object, objects in a Set (mathematics), set, which may or may not hold. As an example, "''is less than''" is a relation on the set of natural numbers; it holds, for instance, between the values and (denoted as ), and likewise between and (denoted as ), but not between the values and nor between and , that is, and both evaluate to false. As another example, "''is sister of'' is a relation on the set of all people, it holds e.g. between Marie Curie and Bronisława Dłuska, and likewise vice versa. Set members may not be in relation "to a certain degree" – either they are in relation or they are not. Formally, a relation over a set can be seen as a set of ordered pairs of members of . The relation holds between and if is a member of . For example, the relation "''is less than''" on the natural numbers is an infinite set of pairs of natural numbers that contains both and , b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
