Displaying similar documents to “Semi-simple Carrousels and the Monodromy”

Prime factors of class number of cyclotomic fields

Tetsuya Taniguchi (2008)

Journal de Théorie des Nombres de Bordeaux

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Let p be an odd prime, r be a primitive root modulo p and r i ≡ r i ( mod p ) with 1 ≤ r i ≤ p - 1 . In 2007, R. Queme raised the question whether the ℓ -rank ( ℓ an odd prime ≠ p ) of the ideal class group of the p -th cyclotomic field is equal to the degree of the greatest common divisor over the finite field 𝔽 ℓ of x ( p - 1 ) / 2 + 1 and Kummer’s polynomial f ( x ) = ∑ i = 0 p - 2 r - i x i . In this paper, we shall give the complete answer for this question enumerating a counter-example.

Wilson’s theorem

Chandan Singh Dalawat (2009)

Journal de Théorie des Nombres de Bordeaux

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We show how K. Hensel could have extended Wilson’s theorem from Z to the ring of integers 𝔬 in a number field, to find the product of all invertible elements of a finite quotient of 𝔬 .

Obstructions to deforming curves on a 3 -fold, II: Deformations of degenerate curves on a del Pezzo 3 -fold

Hirokazu Nasu (2010)

Annales de l’institut Fourier

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We study the Hilbert scheme Hilb s c V of smooth connected curves on a smooth del Pezzo 3 -fold V . We prove that any degenerate curve C , any curve C contained in a smooth hyperplane section S of V , does not deform to a non-degenerate curve if the following two conditions are satisfied: (i) χ ( V , ℐ C ( S ) ) ≥ 1 and (ii) for every line ℓ on S such that ℓ ∩ C = ∅ , the normal bundle N ℓ / V is trivial (  N ℓ / V ≃ 𝒪 ℙ 1 ⊕ 2 ). As a consequence, we prove an analogue (for Hilb s c V ) of a conjecture of J. O. Kleppe, which is concerned with non-reduced components...

Quadratic Differentials and Equivariant Deformation Theory of Curves

Bernhard Köck, Aristides Kontogeorgis (2012)

Annales de l’institut Fourier

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Given a finite p -group G acting on a smooth projective curve X over an algebraically closed field k of characteristic p , the dimension of the tangent space of the associated equivariant deformation functor is equal to the dimension of the space of coinvariants of G acting on the space V of global holomorphic quadratic differentials on X . We apply known results about the Galois module structure of Riemann-Roch spaces to compute this dimension when G is cyclic or when the action of G on...

Computing limit linear series with infinitesimal methods

Laurent Evain (2007)

Annales de l’institut Fourier

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Alexander and Hirschowitz determined the Hilbert function of a generic union of fat points in a projective space when the number of fat points is much bigger than the greatest multiplicity of the fat points. Their method is based on a lemma which determines the limit of a linear system depending on fat points approaching a divisor. Other Hilbert functions were computed previously by Nagata. In connection with his counter-example to Hilbert’s fourteenth problem, Nagata determined...