40 results on '"*OPERATIONS (Algebraic topology)"'
Search Results
2. RELATION BETWEEN MULTIALGEBRAS AND BOOLEAN ALGEBRAS WITH OPERATOR.
- Author
-
Xhaferi, Miranda, Ibraimi, Alit, Sadiki, Flamure, and Rasimi, Krutan
- Subjects
ALGEBRA ,BOOLEAN algebra ,ALGEBRAIC logic ,SET theory ,OPERATIONS (Algebraic topology) - Abstract
In this paper, we will show that based on the concept of multialgebras and relying on the power structures of these algebras, which we could also consider as relational structures, and adding the set of operations ... we get a Boolean algebra with operator. The power structure of relational structure = (A,) is an algebra with the set (A) and the set of all basic operations defined. [ABSTRACT FROM AUTHOR]
- Published
- 2019
3. Semi-Bounded Sets with Respect to Bornological Sets.
- Author
-
Imran, Anwar N., Rakhimov, Isamiddin S., and Hussain, Syarifah Kartini Said
- Subjects
- *
BORNOLOGICAL spaces , *MATHEMATICAL bounds , *SET theory , *OPERATIONS (Algebraic topology) , *MATHEMATICAL analysis - Abstract
The first goal of the present paper is to provide an introduction to the concept of semi bounded set and it is variations in bornological sets (BS). We study semi boundedness properties and keep track behaviour of semi boundedness under some set operations. Then, the concept of bornological ideal (BI) is given. It is provoked by intention to give the definition of semi boundedness with respect to (BI). It extends the notion of semi bounded sets in (BS). Finally, we study some properties of semi bounded sets with respect to a bornological ideal. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
4. Possibility Neutrosophic Vague Soft Expert Set for Decision under Uncertainty.
- Author
-
Hassan, Nasruddin and Al-Quran, Ashraf
- Subjects
- *
SOFT sets , *NEUTROSOPHIC logic , *UNCERTAINTY , *OPERATIONS (Algebraic topology) , *SET theory - Abstract
In this paper, we extend the notion of classical soft expert sets to possibility neutrosophic vague soft expert sets by applying the theory of soft expert sets to possibility neutrosophic vague soft sets. The subset, complement, union, intersection, AND and OR operations as well as some related concepts pertaining to this notion are defined. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
5. On the local closure of clones on countable sets.
- Author
-
Aichinger, Erhard
- Subjects
- *
SET theory , *QUASIGROUPS , *OPERATIONS (Algebraic topology) , *MATHEMATICAL functions , *INVARIANT sets - Abstract
We consider clones on countable sets. If such a clone has quasigroup operations, is locally closed and countable, then there is a function $${f : \mathbb{N} \rightarrow \mathbb{N}}$$ such that the n-ary part of C is equal to the n-ary part of Pol $${{\rm Inv}^{[f(n)]} C}$$ , where $${{\rm Inv}^{[f(n)]} C}$$ denotes the set of f( n)-ary invariant relations of C. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
6. SOME PROPERTIES OF SEQUENCE SPACE BV⌢θ (f, p, q, s).
- Author
-
IşIK, MAHMUT
- Subjects
- *
SEQUENCE spaces , *VECTOR spaces , *MATHEMATICAL mappings , *SET theory , *OPERATIONS (Algebraic topology) , *MATHEMATICAL models - Abstract
In this paper, we define the sequence space BV ⌢θ (f, p, q, s) on a seminormed complex linear space, by using a Modulus function. We give various properties and some inclusion relations on this space. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
7. ON CONSTRUCTION OF ORTHOGONAL d-ARY OPERATIONS.
- Author
-
Markovski, Smile and Mileva, Aleksandra
- Subjects
- *
ORTHOGONALIZATION , *HYPERCUBES , *OPERATIONS (Algebraic topology) , *QUASIGROUPS , *SET theory - Abstract
A d-hypercube of order n is an n × ··· × nd (d times) array with nd elements from a set Q of cardinality n. We recall several connections between d-hypercubes of order n and d-ary operations of order n. We give constructions of orthogonal d-ary operations that generalize a result of Belyavskaya and Mullen. Our main result is a general construction of d-orthogonal d-ary operations from d-ary quasigroups. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
8. Basic operations for fuzzy multisets.
- Author
-
Riesgo, Á., Alonso, P., Díaz, I., and Montes, S.
- Subjects
- *
FUZZY sets , *SET theory , *FUZZY logic , *FUZZY algorithms , *OPERATIONS (Algebraic topology) - Abstract
In their original and ordinary formulation, fuzzy sets associate each element in a reference set with one number, the membership value, in the real unit interval [ 0 , 1 ] . Among the various existing generalisations of the concept, we find fuzzy multisets. In this case, membership values are multisets in [ 0 , 1 ] rather than single values. Mathematically, they can also be seen as a generalisation of the hesitant fuzzy sets, but in this general environment, the information about repetition is not lost, so that, the opinions given by the experts are better managed. Thus, we focus our study on fuzzy multisets and their basic operations: complement, union and intersection. Moreover, we show how the hesitant operations can be worked out from an extension of the fuzzy multiset operations and investigate the important role that the concepts of order and sorting sequences play in the basic difference between these two related approaches. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
9. A new approach to soft uniform spaces.
- Author
-
ÖZTÜRK, Taha Yasin
- Subjects
- *
UNIFORM spaces , *MATHEMATICAL functions , *OPERATIONS (Algebraic topology) , *SET theory , *TOPOLOGICAL spaces , *MATHEMATICAL analysis - Abstract
The purpose of this paper is to introduce the concept of soft uniform spaces and the relationships between soft uniform spaces and uniform spaces. The notions of soft uniform structure, soft uniform continious function, and operations on soft uniform space are introduced and their basic properties are investigated. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
10. γ -Operation in M-Topological Space.
- Author
-
El-Sheikh, S. A., Omar, R. A. K., and Raafat, M.
- Subjects
- *
TOPOLOGICAL spaces , *SET theory , *OPERATIONS (Algebraic topology) , *MATHEMATICS theorems , *MATHEMATICS - Abstract
n this paper we extend the notions of γ-operation, pre-open msets, α-open msets, semi open msets, b-open msets and β-open msets to M-topological spaces. These types of msets are new classes of multisets. We study the rela- tions between these different types of submsets of M-topological spaces. Also, we study some of their properties and show that these types generalize the notion of open (closed) msets. [ABSTRACT FROM AUTHOR]
- Published
- 2015
11. On the number of finite algebraic structures.
- Author
-
Aichinger, Erhard, Mayr, Peter, and McKenzie, Ralph
- Subjects
- *
ALGEBRAIC varieties , *ALGEBRAIC geometry , *OPERATIONS (Algebraic topology) , *MATHEMATICAL equivalence , *SET theory - Abstract
We prove that every clone of operations on a finite set A, if it contains a Malcev operation, is finitely related--i.e., identical with the clone of all operations respecting R for some finitary relation R over A. It follows that for a fixed finite set A, the set of all such Malcev clones is countable. This completes the solution of a problem that was first formulated in 1980, or earlier: how many Malcev clones can finite sets support? More generally, we prove that every finite algebra with few subpowers has a finitely related clone of term operations. Hence modulo term equivalence and a renaming of the elements, there are only countably many finite algebras with few subpowers, and thus only countably many finite algebras with a Malcev term. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
12. HOMOLOGY OPERATIONS IN SYMMETRIC HOMOLOGY.
- Author
-
AULT, SHAUN V.
- Subjects
- *
HOMOLOGY theory , *FUNCTOR theory , *SYMMETRIC functions , *OPERATIONS (Algebraic topology) , *SET theory - Abstract
The symmetric homology of a unital associative algebra A over a commutative ground ring k, denoted HS*(A), is defined using derived functors and the symmetric bar construction of Fiedorowicz. In this paper we show that HS*(A) admits homology operations and a Pontryagin product structure making HS*(A) an associative commutative graded algebra. This is done by finding an explicit E∞ structure on the standard chain groups that compute symmetric homology. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
13. A parallel optical implementation of arithmetic operations
- Author
-
Rudi, Ali Gholami and Jalili, Saeed
- Subjects
- *
OPTICAL processors , *OPERATIONS (Algebraic topology) , *ARITHMETIC functions , *SET theory , *PROBLEM solving , *ELECTRONIC equipment , *DATA transmission systems - Abstract
Abstract: In this paper we present an optical processor for performing arithmetic operations in parallel. The implementation of arithmetic operations makes it possible to perform various computational tasks. As case studies we solve the bounded subset sum problem in parallel and perform parallel primality testing. The processor uses two-dimensional optoelectronic planes for both performing logic operations and storing data, which eliminates the need for transferring data from electronic devices in each step of the computation. The presented processor seems easier to realize than most of the past parallel optical processors due to its simpler and more compact architecture, while staying powerful enough to carry out computations from diverse applications. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
14. A NOTE ON *w-NOETHERIAN DOMAINS.
- Author
-
CHUL JU HWANG and JUNG WOOK LIM
- Subjects
- *
NOETHERIAN rings , *INTEGRALS , *QUOTIENT rings , *SET theory , *HILBERT space , *OPERATIONS (Algebraic topology) - Abstract
Let D be an integral domain with quotient field K, * be a staroperation on D, and GV *(D) be the set of finitely generated ideals J of D such that J* = D. Then the map *w defined by I*w = {x Є K | Jx ⊆ I for some J Є GV *(D)} for all nonzero fractional ideals I of D is a finite character staroperation on D. In this paper, we study several properties of *w-Noetherian domains. In particular, we prove the Hilbert basis theorem for *w-Noetherian domains. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
15. Ordinal operations on graph representations of sets.
- Author
-
Kirby, LaurENce
- Subjects
- *
ORDINAL numbers , *VON Neumann algebras , *MULTIPLY transitive groups , *OPERATIONS (Algebraic topology) , *GRAPH theory - Abstract
Any set x is uniquely specified by the graph of the membership relation on the set obtained by adjoining x to the transitive closure of x. Thus any operation on sets can be looked at as an operation on these graphs. We look at the operations of ordinal arithmetic of sets in this light. This turns out to be simplest for a modified ordinal arithmetic based on the Zermelo ordinals, instead of the usual von Neumann ordinals. In this arithmetic, addition of sets corresponds to concatenating graphs, and multiplication corresponds to replacing each edge of a graph by a copy of another graph. Characterizations for the von Neumann case are also given. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
16. Regularity of Semihypergroups induced by subsets of Semigroups.
- Author
-
Asokkumar, A. and Velrajan, M.
- Subjects
- *
SUBSET selection , *SEMIGROUPS (Algebra) , *MATHEMATICS , *OPERATIONS (Algebraic topology) , *SET theory - Abstract
LetSbe a semigroup andPbe a nonempty subset ofS. If we define a hyperoperation ○ onSbyx○y=xPyfor allx,y∈S, then (S, ○) is a semihypergroup and is denoted by (S,P) . In this paper we get conditions onSandPso that (S,P) is a regular semihypergroup. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
17. Operations on Soft Sets Revisited.
- Author
-
Ping Zhu and Qiaoyan Wen
- Subjects
- *
SOFT sets , *SET theory , *MATHEMATICAL models , *INTERSECTION numbers , *ALGEBRA , *COMPLEMENTARITY constraints (Mathematics) , *OPERATIONS (Algebraic topology) - Abstract
The concept of soft sets introduced by Molodtsov is a general mathematical tool for dealing with uncertainty. Just as the conventional set-theoretic operations of intersection, union, complement, and difference, some corresponding operations on soft sets have been proposed. Unfortunately, such operations cannot keep all classical set-theoretic laws true for soft sets. In this paper, we redefine the intersection, complement, and difference of soft sets and investigate the algebraic properties of these operations along with a known union operation. We find that the new operation system on soft sets inherits all basic properties of operations on classical sets, which justifies our definitions. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
18. New operation compact spaces.
- Author
-
Hussain, Sabir
- Subjects
- *
COMPACT spaces (Topology) , *OPERATIONS (Algebraic topology) , *STOCHASTIC convergence , *MATHEMATICAL mappings , *SET theory - Abstract
In this paper, our main tool is the use of mapping &bgr;:SO(X) ->P(X) from the semi-open set into power set P(X) of the underlying set X, having the property of mono- tonicity and A ⫅&bgr;(A) for each semi-open sets A, where &bgr;(A) denotes the value of A under &bgr;. Moreover, the operation &bgr; generalize the notions and characterizations defined and discussed using the operation &agr; defined and discussed by Kasahara[6]. [ABSTRACT FROM AUTHOR]
- Published
- 2012
19. Equivariant simplicial cohomology with local coefficients and its classification
- Author
-
Mukherjee, Goutam and Sen, Debasis
- Subjects
- *
OPERATIONS (Algebraic topology) , *GROUP actions (Mathematics) , *ISOMORPHISM (Mathematics) , *SET theory , *DISCRETE groups , *MATHEMATICAL analysis , *DISCRIMINANT analysis - Abstract
Abstract: We introduce equivariant twisted cohomology of a simplicial set equipped with simplicial action of a discrete group and prove that for suitable twisting function induced from a given equivariant local coefficients, the simplicial version of Bredon–Illman cohomology with local coefficients is isomorphic to equivariant twisted cohomology. The main aim of this paper is to prove a classification theorem for equivariant simplicial cohomology with local coefficients. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
20. Über Pro- p-Fundamentalgruppen markierter arithmetischer Kurven.
- Author
-
Schmidt, Von Alexander
- Subjects
- *
SET theory , *MAXIMA & minima , *DIRICHLET forms , *DIRICHLET problem , *ARITHMETIC , *OPERATIONS (Algebraic topology) - Abstract
Let k be a global field, p an odd prime number different from char( k) and S, T disjoint, finite sets of primes of k. Let be the Galois group of the maximal p-extension of k which is unramified outside S and completely split at T. We prove the existence of a finite set of primes S0, which can be chosen disjoint from any given set ℳ of Dirichlet density zero, such that the cohomology of coincides with the étale cohomology of the associated marked arithmetic curve. In particular, . Furthermore, we can choose S0 in such a way that realizes the maximal p-extension k( p) of the local field k for all ∈ S ∪ S0, the cup-product is surjective and the decomposition groups of the primes in S establish a free product inside . This generalizes previous work of the author where similar results were shown in the case T = ∅︀ under the restrictive assumption p ∤ #Cl( k) and ζ p ∉ k. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
21. Cancellation properties in ideal systems: A classification of e.a.b. semistar operations
- Author
-
Fontana, Marco and Loper, K. Alan
- Subjects
- *
LINEAR operators , *OPERATIONS (Algebraic topology) , *MODULAR arithmetic , *NUMERICAL analysis , *SET theory , *EQUIVALENCE classes (Set theory) - Abstract
Abstract: We give a classification of e.a.b. semistar (and star) operations by defining four different (successively smaller) distinguished classes. Then, using a standard notion of equivalence of semistar (and star) operations to partition the collection of all e.a.b. semistar (or star) operations, we show that there is exactly one operation of finite type in each equivalence class and that this operation has a range of nice properties. We give examples to demonstrate that the four classes of e.a.b. semistar (or star) operations we defined can all be distinct. In particular, we solve the open problem of showing that a.b. is really a stronger condition than e.a.b. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
22. Maximal Hyperclones on E2 as Hypercores.
- Author
-
Machida, Hajime and Pantović, Jovanka
- Subjects
CLONES (Algebra) ,OPERATIONS (Algebraic topology) ,LATTICE theory ,SET theory ,LOGIC - Abstract
The set of clones of operations on {0, 1} forms a countable lattice which was classified by Post. The cardinality of the lattice of hyperclones on {0, 1} was proved by Machida to be of the continuum. A hyperclone C
1 is a hypercore of a clone C if its extension C1 # is contained in C and C1 is not contained in any other hyperclone having the same property. We describe six maximal hyperclones on the two-elements set as hypercores of particular clones on three element set. The interval of hyperclones on {0, 1} between the clone of all projections and the one generated by all unary hyperoperations is also completely determined. [ABSTRACT FROM AUTHOR]- Published
- 2009
23. FUZZY ARROW'S THEOREM.
- Author
-
MORDESON, JOHN N. and CLARK, TERRY D.
- Subjects
- *
FUZZY numbers , *SET theory , *OPERATIONS (Algebraic topology) , *FUZZY algorithms , *BINARY number system - Abstract
In this paper, we prove a fuzzy version of Arrow's Theorem that contains the crisp version. We show that under our definitions, Arrow's Theorem remains intact even if levels of intensities of the players and levels of membership in the set of alternatives are considered. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
24. An algebraic model for chains on $\Omega BG{}^{^\wedge }_p$.
- Subjects
- *
OPERATIONS (Algebraic topology) , *HOMOTOPY theory , *FINITE groups , *SET theory , *FIBER bundles (Mathematics) , *MATHEMATICAL models - Abstract
We provide an interpretation of the homology of the loop space on the $p$-completion of the classifying space of a finite group in terms of representation theory, and demonstrate how to compute it. We then give the following reformulation. If $f$ is an idempotent in $kG$ such that $f.kG$ is the projective cover of the trivial module $k$, and $e=1-f$, then we exhibit isomorphisms for $nge 2$: begin {align*} H_n(Omega BG {}^{^wedge }_p;k) &cong mathrm {Tor}_{n-1}^{e.kG.e}(kG.e,e.kG), H^n(Omega BG{}^{^wedge }_p;k) &cong mathrm {Ext}^{n-1}_{e.kG.e}(e.kG,e.kG). endalign* }}} Further algebraic structure is examined, such as products and coproducts, restriction and Steenrod operations. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
25. On endomorphism rings and dimensions of local cohomology modules.
- Subjects
- *
ENDOMORPHISM rings , *OPERATIONS (Algebraic topology) , *MODULES (Algebra) , *GORENSTEIN rings , *ISOMORPHISM (Mathematics) , *SET theory - Abstract
Let $(R,mathfrak m)$ denote an $n$-dimensional complete local Gorenstein ring. For an ideal $I$ of $R$ let $H^i_I(R), i in mathbb Z,$ denote the local cohomology modules of $R$ with respect to $I.$ If $H^i_I(R) = 0$ for all $i not = c = operatorname {height} I,$ then the endomorphism ring of $H^c_I(R)$ is isomorphic to $R$. Here we prove that this is true if and only if $H^i_I(R) = 0$ for $i = n, n-1$, provided $c geq 2$ and $R/I$ has an isolated singularity, resp. if $I$ is set-theoretically a complete intersection in codimension at most one. Moreover, there is a vanishing result of $H^i_I(R)$ for all $i > m, m$ a given integer, and an estimate of the dimension of $H^i_I(R).$ [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
26. Top Local Cohomology Modules with Specified Attached Primes.
- Author
-
Dibaei, Mohammad T. and Jafari, Raheleh
- Subjects
- *
ALGEBRAIC topology , *OPERATIONS (Algebraic topology) , *SET theory , *CONTINUUM hypothesis , *COMBINATORIAL set theory - Abstract
Let (R, 픪) be a complete Noetherian local ring and let M be a finite R-module of positive Krull dimension n. It is shown that any subset T of AsshR(M) can be expressed as the set of attached primes of the top local cohomology module ${\rm H}^n_{\frak a}(M)$ for some ideal 픞 of R. Moreover, if 픞 is an ideal of R such that the set of attached primes of ${\rm H}^n_{\frak a}(M)$ is a non-empty proper subset of AsshR(M), then ${\rm H}^n_{\frak a}(M)\cong {\rm H}^n_{\frak b}(M)$ for some ideal 픟 of R with dimR(R/픟) = 1. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
27. INERTIA AND DELOCALIZED TWISTED COHOMOLOGY.
- Author
-
Bunke, Ulrich, Schick, Thomas, and Spitzweck, Markus
- Subjects
- *
OPERATIONS (Algebraic topology) , *TOPOLOGICAL spaces , *ALGEBRAIC topology , *SET theory , *K-spaces - Abstract
Orbispaces are the analog of orbifolds, where the category of manifolds is replaced by topological spaces. We construct the loop orbispace LX of an orbispace X in the language of stacks in topological spaces. Furthermore, to a twist given by a U(1)-banded gerbe G → X we associate a U(1)δ-principal bundle G˜δ → LX. We use sheaf theory on topological stacks in order to define the delocalized twisted cohomology by H*deloc(X,G) := 8(GL, f*L L), where fL : GL → LX is the pull-back of the gerbe G → X via the natural map LX → X, and L ϵ ShAbLX is the sheaf of sections of the ℂδ-bundle associated to G˜δ → LX. The same constructions can be applied in the case of orbifolds, and we show that the sheaf theoretic delocalized twisted cohomology is isomorphic to the twisted de Rham cohomology, where the isomorphism depends on the choice of a geometric structure on the gerbe G → X. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
28. COFIBRANT OBJECTS AMONG HIGHER-DIMENSIONAL CATEGORIES.
- Author
-
Métayer, François
- Subjects
- *
OPERATIONS (Algebraic topology) , *TOPOLOGICAL spaces , *ALGEBRAIC topology , *SET theory , *K-spaces - Abstract
We define a notion of cofibration among ∞-categories and show that the cofibrant objects are exactly the free ones, that is, those generated by polygraphs. [ABSTRACT FROM AUTHOR]
- Published
- 2008
29. APPROXIMATE MAL'TSEV OPERATIONS.
- Author
-
Bourn, Dominique and Janelidze, Zurab
- Subjects
- *
APPROXIMATE identities (Algebra) , *OPERATIONS (Algebraic topology) , *MORPHISMS (Mathematics) , *CATEGORIES (Mathematics) , *SET theory , *TRANSFORMATION groups , *GROUP theory , *MATHEMATICAL transformations , *HOMEOMORPHISMS , *TOPOLOGICAL transformation groups - Abstract
Let X and A be sets and α : X → A a map between them. We call a map μ : X × X × X → A an approximate Mal'tsev operation with approximation α, if it satisfies μ(x, y, y) = α(x) = μ(y, y, x) for all x, y ∊ X. Note that if A = X and the approximation α is an identity map, then μ becomes an ordinary Mal'tsev operation. We prove the following two characterization theorems: a category 핏 is a Mal'tsev category if and only if in the functor category Set핏op×핏 there exists an internal approximate Mal'tsev operation hom핏× hom핏 × hom핏 → A whose approximation α satisfies a suitable condition; a regular category 핏 with finite coproducts is a Mal'tsev category, if and only if in the functor category 핏핏 there exists an internal approximate Mal'tsev cooperation A → 1핏 + 1핏 + 1핏 whose approximation α is a natural transformation with every component a regular epimorphism in 핏. Note that in both of these characterization theorems, if require further the approximation α to be an identity morphism, then the conditions there involving α become equivalent to 핏 being a naturally Mal'tsev category. [ABSTRACT FROM AUTHOR]
- Published
- 2008
30. CHEN–RUAN COHOMOLOGY OF ADE SINGULARITIES.
- Author
-
PERRONI, FABIO
- Subjects
- *
OPERATIONS (Algebraic topology) , *ORBIFOLDS , *ALGEBRAIC topology , *HOMOLOGY theory , *ISOMORPHISM (Mathematics) , *SET theory , *MANIFOLDS (Mathematics) , *DIFFERENTIAL geometry , *TOPOLOGY - Abstract
We study Ruan's cohomological crepant resolution conjecture [41] for orbifolds with transversal ADE singularities. In the An-case, we compute both the Chen–Ruan cohomology ring $H_{\rm CR}^{*}([Y])$ and the quantum corrected cohomology ring H*(Z)(q1,...,qn). The former is achieved in general, the later up to some additional, technical assumptions. We construct an explicit isomorphism between $H_{\rm CR}^{*}([Y])$ and H*(Z)(-1) in the A1-case, verifying Ruan's conjecture. In the An-case, the family H*(Z)(q1,...,qn) is not defined for q1 = ⋯ = qn = -1. This implies that the conjecture should be slightly modified. We propose a new conjecture in the An-case (Conjecture 1.9). Finally, we prove Conjecture 1.9 in the A2-case by constructing an explicit isomorphism. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
31. On Witt vector cohomology for singular varieties.
- Author
-
Pierre Berthelot, Spencer Bloch, and Hélène Esnault
- Subjects
- *
ARITHMETICAL algebraic geometry , *MORPHISMS (Mathematics) , *ALGEBRAIC geometry , *SET theory , *HOMOLOGY theory , *OPERATIONS (Algebraic topology) - Abstract
Over a perfect field $k$ of characteristic $p > 0$, we construct a ‘Witt vector cohomology with compact supports’ for separated $k$-schemes of finite type, extending (after tensorization with ${\mathbb Q}$) the classical theory for proper $k$-schemes. We define a canonical morphism from rigid cohomology with compact supports to Witt vector cohomology with compact supports, and we prove that it provides an identification between the latter and the slope ${<}1$ part of the former. Over a finite field, this allows one to compute congruences for the number of rational points in special examples. In particular, the congruence modulo the cardinality of the finite field of the number of rational points of a theta divisor on an abelian variety does not depend on the choice of the theta divisor. This answers positively a question by J.-P. Serre. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
32. Cohomology of regular differential forms for affine curves
- Author
-
Bonnet, Philippe
- Subjects
- *
OPERATIONS (Algebraic topology) , *ALGEBRAIC topology , *DIFFERENTIAL geometry , *SET theory - Abstract
Abstract: Let C be a complex affine reduced curve, and denote by its first truncated cohomology group, i.e. the quotient of all regular differential 1-forms by exact 1-forms. First we introduce a nonnegative invariant that measures the complexity of the singularity of C at the point x, and we establish the following formula: where denotes the first singular homology group of C with complex coefficients. Second we consider a family of curves given by the fibres of a dominant morphism , where X is an irreducible complex affine surface. We analyze the behaviour of the function . More precisely we show that it is constant on a Zariski open set, and that it is lower semi-continuous in general. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
- View/download PDF
33. PERIODICITY IN GROUP COHOMOLOGY AND COMPLETE RESOLUTIONS.
- Author
-
OLYMPIA TALELLI
- Subjects
OPERATIONS (Algebraic topology) ,ALGEBRAIC topology ,SET theory ,FUNCTOR theory ,HOMOLOGICAL algebra ,FUNCTIONAL analysis - Abstract
A group $G$ is said to have periodic cohomology with period $q$ after $k$ steps, if the functors $H^{i}(G,-)$ and $H^{i+q}(G,-)$ are naturally equivalent for all $i>k$. Mislin and the author have conjectured that periodicity in cohomology after some steps is the algebraic characterization of those groups $G$ that admit a finite-dimensional, free $G$-CW-complex, homotopy equivalent to a sphere. This conjecture was proved by Adem and Smith under the extra hypothesis that the periodicity isomorphisms are given by the cup product with an element in $H^q (G,\mathbb{Z})$. It is expected that the periodicity isomorphisms will always be given by the cup product with an element in $H^q (G,\mathbb{Z})$; this paper shows that this is the case if and only if the group $G$ admits a complete resolution and its complete cohomology is calculated via complete resolutions. It is also shown that having the periodicity isomorphisms given by the cup product with an element in $H^q (G,\mathbb{Z})$ is equivalent to silp $G$ being finite, where silp $G$ is the supremum of the injective lengths of the projective $\mathbb{Z}G$-modules. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
34. Structure of Ann-Categories of Type (R, N).
- Author
-
Nguyen Tien Quang
- Subjects
- *
SET theory , *MORPHISMS (Mathematics) , *MATHEMATICS , *OPERATIONS (Algebraic topology) , *ALGEBRAIC topology , *TOPOLOGY - Abstract
Ann-category is called almost strict if its natural equivalences, except a natural equivalence of commutativity and of the distributivity, are identities. The purpose of this paper is to prove that every Ann-category is Ann-equivalent to an almost strict Ann-category of the type (R, M) and to give new interpretations of the cohomology groups H3 (R, M) of the rings R. The present paper consists, in a certain sense, of an extension of our results in [4-6]. Reading the present paper requires certain knowledge of the main results, which were announced in [3]. For completeness, we briefly recall some of the material that will be indispensable for the understanding of this paper. Throughout this paper, for the tensorial product of two objects A and B, we write AB instead of A ⊗ B, but for the morphisms we still write f ⊗ g to avoid confusion with composition. [ABSTRACT FROM AUTHOR]
- Published
- 2004
35. Weil-étale cohomology over finite fields.
- Author
-
Thomas Geisser
- Subjects
OPERATIONS (Algebraic topology) ,ALGEBRAIC topology ,TOPOLOGY ,SET theory - Abstract
We calculate the derived functors R ?
* for the base change ? from the Weil-étale site to the étale site for a variety over a finite field. For smooth and proper varieties, we apply this to express Tate’s conjecture and Lichtenbaum’s conjecture on special values of ?-functions in terms of Weil-étale cohomology of the motivic complex Z( n). [ABSTRACT FROM AUTHOR]- Published
- 2004
- Full Text
- View/download PDF
36. Complete sets of relations in the cohomology rings of moduli spaces of holomorphic bundles and parabolic bundles over a Riemann surface.
- Author
-
Richard Earl and Frances Kirwan
- Subjects
OPERATIONS (Algebraic topology) ,MODULI theory ,HOLOMORPHIC functions ,RIEMANN surfaces ,SET theory ,BETWEENNESS relations (Mathematics) ,RELATION algebras - Abstract
The cohomology ring of the moduli space of stable holomorphic vector bundles of rank $n$ and degree $d$ over a Riemann surface of genus $g > 1$ has a standard set of generators when $n$ and $d$ are coprime. When $n = 2$ the relations between these generators are well understood, and in particular a conjecture of Mumford, that a certain set of relations is a complete set, is known to be true. In this article generalisations are given of Mumford's relations to the cases when $n > 2$ and also when the bundles are parabolic bundles, and these are shown to form complete sets of relations. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
37. Cohomological descent of rigid cohomology for proper coverings.
- Author
-
Tsuzuki, Nobuo
- Subjects
ALGEBRAIC topology ,DYER-Lashof operations ,OPERATIONS (Algebraic topology) ,HOMOLOGY theory ,TOPOLOGY ,SET theory - Abstract
We prove that the cohomological descent for proper hypercoverings holds true in rigid cohomology. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
38. A Gap Cohomology Group.
- Author
-
Morgan, Charles
- Subjects
- *
SET theory , *ISOMORPHISM (Mathematics) , *EQUIVALENCE relations (Set theory) , *OPERATIONS (Algebraic topology) , *TOWERS - Abstract
The article focuses on the gap cohomology group of a tower defined by Dan Talayco. It states that this group is isomorphic to the collection of gaps in the tower modulo the equivalence relation given by two gaps being equivalent if their symmetric difference is not a gap in the tower. It notes that Talayco shows that there is always some tower whose gap cohomology group has size 2.
- Published
- 1995
- Full Text
- View/download PDF
39. Generalisation of roughness bounds in rough set operations
- Author
-
Yang, Yingjie and John, Robert I.
- Subjects
- *
SET theory , *SURFACE roughness , *MATHEMATICS , *OPERATIONS (Algebraic topology) - Abstract
Abstract: This paper investigates the general roughness bounds for rough set operations. Compared with set-oriented rough sets, the results prove that the same upper bound of the roughness for the union, difference and complement operation could be determined by the roughness of the two operand sets. However, the lower roughness bounds of set-oriented rough sets operations do not hold for other rough sets. We provide an example to show the derived bounds from the operand’s roughness. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
40. Fixed points of commutative Lüders operations.
- Author
-
Liu Weihua and Wu Junde
- Subjects
- *
FIXED point theory , *COMMUTATIVE algebra , *SET theory , *OPERATIONS (Algebraic topology) , *QUANTUM theory - Abstract
This paper verifies a conjecture posed in a pair of papers on the fixed point sets for a class of quantum operations. Specifically, it is proved that if a quantum operation has mutually commuting operation elements that are effects forming a resolution of the identity, then the fixed point set of the quantum operation is exactly the commutant of the operation elements. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.