638 research outputs found

    Cohomology and the Brauer groups of diagonal surfaces

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    We present a method for calculating the Brauer group of a surface given by a diagonal equation in the projective space. For diagonal quartic surfaces with coefficients in Q we determine the Brauer groups over Q and Q(i).Comment: 45 page

    Constructing genus 3 hyperelliptic Jacobians with CM

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    Given a sextic CM field KK, we give an explicit method for finding all genus 3 hyperelliptic curves defined over C\mathbb{C} whose Jacobians are simple and have complex multiplication by the maximal order of this field, via an approximation of their Rosenhain invariants. Building on the work of Weng, we give an algorithm which works in complete generality, for any CM sextic field KK, and computes minimal polynomials of the Rosenhain invariants for any period matrix of the Jacobian. This algorithm can be used to generate genus 3 hyperelliptic curves over a finite field Fp\mathbb{F}_p with a given zeta function by finding roots of the Rosenhain minimal polynomials modulo pp.Comment: 20 pages; to appear in ANTS XI
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