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Łukasiewicz–Moisil Algebra
Łukasiewicz–Moisil algebras (LM''n'' algebras) were introduced in the 1940s by Grigore Moisil (initially under the name of Łukasiewicz algebras) in the hope of giving Algebraic semantics (mathematical logic), algebraic semantics for the ''n''-valued Łukasiewicz logic. However, in 1956 Alan Rose discovered that for ''n'' ≥ 5, the Łukasiewicz–Moisil algebra does not model (mathematical logic), model the Łukasiewicz logic. A faithful model for the ℵ0-valued (infinitely-many-valued) Łukasiewicz–Tarski logic was provided by C. C. Chang's MV-algebra, introduced in 1958. For the axiomatically more complicated (finite) ''n''-valued Łukasiewicz logics, suitable algebras were published in 1977 by Revaz Grigolia and called MV-algebra#MVn-algebras, MV''n''-algebras. MV''n''-algebras are a subclass of LM''n''-algebras, and the inclusion is strict for ''n'' ≥ 5.Iorgulescu, A.: Connections between MV''n''-algebras and ''n''-valued Łukasiewicz-Moisil algebras—I. Discrete Math. 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grigore Moisil
Grigore Constantin Moisil (; 10 January 1906 – 21 May 1973) was a Romanian mathematician, computer pioneer, and list of members of the Romanian Academy, titular member of the Romanian Academy. His research was mainly in the fields of mathematical logic (Łukasiewicz–Moisil algebra), algebraic logic, MV-algebra, and differential equations. He is viewed as the father of computer science in Romania. Moisil was also a member of the Academy of Sciences of Bologna and of the International Institute of Philosophy. In 1996, the IEEE Computer Society awarded him posthumously the ''Computer Pioneer'' Award. Biography Grigore Moisil was born in 1906 in Tulcea into an intellectual family. His great-grandfather, Grigore Moisil (1814–1891), a clergyman, was one of the founders of the George Coșbuc National College (Năsăud), first Romanian high school in Năsăud. His father, Constantin Moisil (1876–1958), was a history professor, archaeology, archaeologist and numismatics, numisma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Morgan Algebra
__NOTOC__ In mathematics, a De Morgan algebra (named after Augustus De Morgan, a British mathematician and logician) is a structure ''A'' = (A, ∨, ∧, 0, 1, ¬) such that: * (''A'', ∨, ∧, 0, 1) is a bounded distributive lattice, and * ¬ is a De Morgan involution: ¬(''x'' ∧ ''y'') = ¬''x'' ∨ ¬''y'' and ¬¬''x'' = ''x''. (i.e. an involution that additionally satisfies De Morgan's laws) In a De Morgan algebra, the laws * ¬''x'' ∨ ''x'' = 1 (law of the excluded middle), and * ¬''x'' ∧ ''x'' = 0 ( law of noncontradiction) do not always hold. In the presence of the De Morgan laws, either law implies the other, and an algebra which satisfies them becomes a Boolean algebra. Remark: It follows that ¬(x ∨ y) = ¬x ∧ ¬y, ¬1 = 0 and ¬0 = 1 (e.g. ¬1 = ¬1 ∨ 0 = ¬1 ∨ ¬¬0 = ¬(1 ∧ ¬0) = ¬¬0 = 0). Thus ¬ is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portugaliae Mathematica
''Portugaliae Mathematica'' is a peer-reviewed scientific journal published by the European Mathematical Society on behalf of the Portuguese Mathematical Society . It covers all branches of mathematics. The journal was established in 1937, by António Aniceto Monteiro, its first editor-in-chief. The journal is abstracted and indexed in ''Zentralblatt MATH'', ''Mathematical Reviews'', the Science Citation Index Expanded, and Current Contents/Physical, Chemical & Earth Sciences. The current editor-in-chief is José Francisco Rodrigues (Universidade de Lisboa). History The scientific journal ''Portugaliae Mathematica'' was founded in 1937 in Lisbon by António Aniceto Monteiro—who had just completed his doctorate under René Maurice Fréchet in Paris—marking the beginning of a distinctly modernist phase in Portuguese mathematical publishing. It inaugurated a period of "mathematical effervescence" that lasted roughly a decade, during which it was successively joined by the '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monadic Boolean Algebra
In abstract algebra, a monadic Boolean algebra is an algebraic structure ''A'' with signature : of type ⟨2,2,1,0,0,1⟩, where ⟨''A'', ·, +, ', 0, 1⟩ is a Boolean algebra. The monadic/unary operator ∃ denotes the existential quantifier, which satisfies the identities (using the received prefix notation for ∃): * * * * is the ''existential closure'' of ''x''. Dual to ∃ is the unary operator ∀, the universal quantifier, defined as . A monadic Boolean algebra has a dual definition and notation that take ∀ as primitive and ∃ as defined, so that . (Compare this with the definition of the dual Boolean algebra.) Hence, with this notation, an algebra ''A'' has signature , with ⟨''A'', ·, +, ', 0, 1⟩ a Boolean algebra, as before. Moreover, ∀ satisfies the following dualized version of the above identities: # # # # . is the ''universal closure'' of ''x''. Discussion Monadic Boolean algebras have an important connection to topo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antonio Monteiro (mathematician)
António Aniceto Monteiro (31 May 1907–29 October 1980) was a mathematician born in Portuguese Angola who later emigrated to Brazil in 1945 and finally to Argentina in 1950. Monteiro is best known for establishing a school of algebraic logic at Universidad Nacional del Sur, Bahía Blanca, Argentina. His efforts to promote theoretical computer science research in Argentina were less successful. After his undergraduate studies at the University of Lisbon (completed in 1930), Monteiro obtained a PhD at Sorbonne in 1936 under the advisement of Maurice Fréchet with a thesis in topology. In Portugal Monteiro was the main founder of the journal ''Portugaliae Mathematica'' in 1937. In 1945 Monteiro moved to Brazil. There are two versions of why Monteiro left Portugal. The first version is that Monteiro and other Portuguese mathematicians like Ruy Luís Gomes fell foul of Salazar's regime for their political beliefs; some, like Gomes, were imprisoned; others, like Monteiro, were s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substructure (mathematics)
In mathematical logic, an (induced) substructure or (induced) subalgebra is a structure whose domain is a subset of that of a bigger structure, and whose functions and relations are restricted to the substructure's domain. Some examples of subalgebras are subgroups, submonoids, subrings, subfields, subalgebras of algebras over a field, or induced subgraphs. Shifting the point of view, the larger structure is called an extension or a superstructure of its substructure. In model theory, the term "submodel" is often used as a synonym for substructure, especially when the context suggests a theory of which both structures are models. In the presence of relations (i.e. for structures such as ordered groups or graphs, whose signature is not functional) it may make sense to relax the conditions on a subalgebra so that the relations on a weak substructure (or weak subalgebra) are ''at most'' those induced from the bigger structure. Subgraphs are an example where the distinction mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subdirect Product
In mathematics, especially in the areas of abstract algebra known as universal algebra, group theory, ring theory, and module theory, a subdirect product is a subalgebra of a direct product that depends fully on all its factors without however necessarily being the whole direct product. The notion was introduced by Birkhoff in 1944, generalizing Emmy Noether's special case of the idea (and decomposition result) for Noetherian rings, and has proved to be a powerful generalization of the notion of direct product. Definition A subdirect product is a subalgebra (in the sense of universal algebra) ''A'' of a direct product Π''iAi'' such that every induced projection (the composite ''pjs'': ''A'' → ''Aj'' of a projection ''p''''j'': Π''iAi'' → ''Aj'' with the subalgebra inclusion ''s'': ''A'' → Π''iAi'') is surjective. A direct (subdirect) representation of an algebra ''A'' is a direct (subdirect) product isomorphic to ''A''. An algebra is called subdirectly irreducible if i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Product
In mathematics, a direct product of objects already known can often be defined by giving a new one. That induces a structure on the Cartesian product of the underlying sets from that of the contributing objects. The categorical product is an abstraction of these notions in the setting of category theory. Examples are the product of sets, groups (described below), rings, and other algebraic structures. The product of topological spaces is another instance. The direct sum is a related operation that agrees with the direct product in some but not all cases. Examples * If \R is thought of as the set of real numbers without further structure, the direct product \R \times \R is just the Cartesian product \. * If \R is thought of as the group of real numbers under addition, the direct product \R\times \R still has \ as its underlying set. The difference between this and the preceding examples is that \R \times \R is now a group and so how to add their elements must also be s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embedding
In mathematics, an embedding (or imbedding) is one instance of some mathematical structure contained within another instance, such as a group (mathematics), group that is a subgroup. When some object X is said to be embedded in another object Y, the embedding is given by some Injective function, injective and structure-preserving map f:X\rightarrow Y. The precise meaning of "structure-preserving" depends on the kind of mathematical structure of which X and Y are instances. In the terminology of category theory, a structure-preserving map is called a morphism. The fact that a map f:X\rightarrow Y is an embedding is often indicated by the use of a "hooked arrow" (); thus: f : X \hookrightarrow Y. (On the other hand, this notation is sometimes reserved for inclusion maps.) Given X and Y, several different embeddings of X in Y may be possible. In many cases of interest there is a standard (or "canonical") embedding, like those of the natural numbers in the integers, the integers i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pointwise
In mathematics, the qualifier pointwise is used to indicate that a certain property is defined by considering each value f(x) of some Function (mathematics), function f. An important class of pointwise concepts are the ''pointwise operations'', that is, operations defined on functions by applying the operations to function values separately for each point in the domain of a function, domain of definition. Important Theory of relations, relations can also be defined pointwise. Pointwise operations Formal definition A binary operation on a set can be lifted pointwise to an operation on the set of all functions from to as follows: Given two functions and , define the function by Commonly, ''o'' and ''O'' are denoted by the same symbol. A similar definition is used for unary operations ''o'', and for operations of other arity. Examples The pointwise addition f+g of two functions f and g with the same domain and codomain is defined by: The pointwise product or pointwise mul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boolean Algebra (structure)
In abstract algebra, a Boolean algebra or Boolean lattice is a complemented distributive lattice. This type of algebraic structure captures essential properties of both set operations and logic operations. A Boolean algebra can be seen as a generalization of a power set algebra or a field of sets, or its elements can be viewed as generalized truth values. It is also a special case of a De Morgan algebra and a Kleene algebra (with involution). Every Boolean algebra gives rise to a Boolean ring, and vice versa, with ring multiplication corresponding to conjunction or meet ∧, and ring addition to exclusive disjunction or symmetric difference (not disjunction ∨). However, the theory of Boolean rings has an inherent asymmetry between the two operators, while the axioms and theorems of Boolean algebra express the symmetry of the theory described by the duality principle. __TOC__ History The term "Boolean algebra" honors George Boole (1815–1864), a self-educated E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endomorphism
In mathematics, an endomorphism is a morphism from a mathematical object to itself. An endomorphism that is also an isomorphism is an automorphism. For example, an endomorphism of a vector space is a linear map , and an endomorphism of a group is a group homomorphism . In general, we can talk about endomorphisms in any category. In the category of sets, endomorphisms are functions from a set ''S'' to itself. In any category, the composition of any two endomorphisms of is again an endomorphism of . It follows that the set of all endomorphisms of forms a monoid, the full transformation monoid, and denoted (or to emphasize the category ). Automorphisms An invertible endomorphism of is called an automorphism. The set of all automorphisms is a subset of with a group structure, called the automorphism group of and denoted . In the following diagram, the arrows denote implication: Endomorphism rings Any two endomorphisms of an abelian group, , can be ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
