Now showing items 134-153 of 211

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      On the centralizer of generic braids  [Article]

      González-Meneses López, Juan; Valladares García, Dolores (De Gruyter, 2018-11)
      We study the centralizer of a braid from the point of view of Garside theory, showing that generically a minimal set of generators can be computed very efficiently, as the ultra summit set of a generic braid has a very ...
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      On the cycling operation in braid groups  [Article]

      González-Meneses López, Juan; Gebhardt, Volker (Elsevier, 2008-09-06)
      The cycling operation is a special kind of conjugation that can be applied to elements in Artin’s braid groups, in order to reduce their length. It is a key ingredient of the usual solutions to the conjugacy problem in ...
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      On the dimension of discrete valuations of k ((X1, ..., Xn))  [Article]

      Olalla Acosta, Miguel Ángel (Elsevier, 2001-07-01)
      Let v be a rank-one discrete valuation of the field Kn=k((X1,…,Xn)). We know, after [1], that if n=2 then the dimension of v is 1 and if v is the usual order function over k((X1,…,Xn)) its dimension is n−1. In this paper ...
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      On the functoriality of cohomology of categories  [Article]

      Muro Jiménez, Fernando (Elsevier, 2006-03)
      In this paper we show that the Baues-Wirsching complex used to define cohomology of categories is a 2-functor from a certain 2-category of natural systems of abelian groups to the 2-category of chain complexes, chain ...
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      On the logarithmic comparison theorem for integrable logarithmic connections  [Article]

      Calderón Moreno, Francisco Javier; Narváez Macarro, Luis (London Mathematical Society, 2009)
      Let X be a complex analytic manifold, D ⊂ X a free divisor with jacobian ideal of linear type (e.g. a locally quasi-homogeneous free divisor), j : U = X − D ֒→ X the corresponding open inclusion, E an integrable logarithmic ...
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      On the modules of m-integrable derivations in non-zero characteristic  [Article]

      Narváez Macarro, Luis (Elsevier, 2012-03-20)
      Let k be a commutative ring and A a commutative k-algebra. Given a positive integer m, or m = ∞, we say that a k-linear derivation δ of A is m-integrable if it extends up to a Hasse–Schmidt derivation D = (Id, D1 = δ, ...
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      On the number of rational points on curves over finite fields with many automorphisms  [Article]

      Rojas León, Antonio (Elsevier, 2013-01)
      Using Weil descent, we give bounds for the number of rational points on two families of curves over finite fields with a large abelian group of automorphisms: Artin–Schreier curves of the form yq−y=f(x) with f∈Fqr[x], on ...
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      On the singular braid monoid of an orientable surface  [Article]

      Díaz Cantos, Jerónimo; González-Meneses López, Juan; Tornero Sánchez, José María (American Mathematical Society, 2004)
      In this paper we show that the singular braid monoid of an orientable surface can be embedded in a group. The proof is purely topological, making no use of the monoid presentation.
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      On the Sn-module structure of the noncommutative harmonics  [Article]

      Briand, Emmanuel; Rosas Celis, Mercedes Helena; Zabrocki, Mike (Elsevier, 2008-08)
      Using the a noncommutative version of Chevalley’s theorem due to Bergeron, Reutenauer, Rosas, and Zabrocki we compute the graded Frobenius series for their two sets of noncommutative harmonics with respect to the left ...
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      On the structure of the centralizer of a braid  [Article]

      González-Meneses López, Juan (Elsevier, 2004)
      The mixed braid groups are the subgroups of Artin braid groups whose elements preserve a given partition of the base points. We prove that the centralizer of any braid can be expressed in terms of semidirect and ...
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      On the ubiquity of trivial torsion on elliptic curves  [Article]

      González Jiménez, Enrique; Tornero Sánchez, José María (Springer, 2010-08)
      The purpose of this paper is to give a down-to-earth proof of the well–known fact that a randomly chosen elliptic curve over the rationals is most likely to have trivial torsion.
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      On the unit of a monoidal model category  [Article]

      Muro Jiménez, Fernando (Elsevier, 2015-08-15)
      In this paper we show how to modify cofibrations in a monoidal model category so that the tensor unit becomes cofibrant while keeping the same weak equivalences. We obtain aplications to enriched categories and coloured ...
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      Ordering pure braid groups on compact, connected surfaces  [Article]

      González-Meneses López, Juan (University of California, 2002-04)
      We prove that the pure braid groups on compact, connected, orientable surfaces are bi-orderable, and that the pure braid groups on compact, connected non-orientable surfaces have generalized torsion, thus they are not ...
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      Pierre Deligne  [Article]

      Rojas León, Antonio (Real Sociedad Matemática Española, 2013)
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      Pilar Pisón Casares, in memoriam  [Article]

      Ojeda Martínez de Castilla, Ignacio; Piedra Sánchez, Ramón (Real Sociedad Matematica Española, 2007)
      Estamos habituados a describir objetos matemáticos, a elaborar teorías, conjeturar resultados, demostrar asertos o refutar hipótesis, pero no a escribir de una persona, más aún si con ella tenemos vínculos afectivos que ...
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      Polynomial braid combing  [Article]

      Flores Díaz, Ramón Jesús; González-Meneses López, Juan (Oxford University Press, 2018)
      We prove that, for n ≥ 3, the minimal dimension of a model of the classifying space of the braid group Bn, and of the pure braid group Pn, with respect to the family of virtually cyclic groups is n.
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      Presentations for the monoids of singular braids on closed surfaces  [Article]

      González-Meneses López, Juan (Taylor & Francis, 2002)
      We give presentations, in terms of generators and relations, for the monoids SBn(M) of singular braids on closed surfaces. The proof of the validity of these presentations can also be applied to verify, in a new way, the ...
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      Primer Encuentro Conjunto RSME-UMA, Buenos Aires, 11 a 15 de diciembre de 2017  [Article]

      Narváez Macarro, Luis; Villamayor Uriburu, Orlando (Real Sociedad Matemática Española, 2018)
      En la semana del lunes 11 al viernes 15 de diciembre de 2017 se llevó a cabo en Buenos Aires el Primer Encuentro Conjunto entre la Unión Matemática Argentina (UMA) y la RSME. Se celebraba el centenario de la primera ...
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      Purity of exponential sums on An  [Article]

      Rojas León, Antonio (Kluwer, 2006-03)
      We give a purity result for two kinds of exponential sums of the type ∑x∈knψ(f(x)), where k is a finite field of characteristic p and ψ:k→C⋆ is a non-trivial additive character. In the first case, f∈k[x1,…,xn] is a polynomial ...
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      Purity of exponential sums on An, II  [Article]

      Rojas León, Antonio (De Gruyer, 2007-03)
      We give a purity result for exponential sums of the type P x∈kn ψ(f(x)), where k is a finite field of characteristic p, ψ : k → C* is a non-trivial additive character and f ∈ k[x1, . . . , xn] is a polynomial whose highest ...