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Binomial squares in pure cubic number fields

Franz Lemmermeyer (2012)

Journal de Théorie des Nombres de Bordeaux

Let K = ( ω ) , with ω 3 = m a positive integer, be a pure cubic number field. We show that the elements α K × whose squares have the form a - ω for rational numbers a form a group isomorphic to the group of rational points on the elliptic curve E m : y 2 = x 3 - m . This result will allow us to construct unramified quadratic extensions of pure cubic number fields K .

Binomials transformation formulae for scaled Fibonacci numbers

Edyta Hetmaniok, Bożena Piątek, Roman Wituła (2017)

Open Mathematics

The aim of the paper is to present the binomial transformation formulae of Fibonacci numbers scaled by complex multipliers. Many of these new and nontrivial relations follow from the fundamental properties of the so-called delta-Fibonacci numbers defined by Wituła and Słota. The paper contains some original relations connecting the values of delta-Fibonacci numbers with the respective values of Chebyshev polynomials of the first and second kind.

Birational geometry of quadrics

Burt Totaro (2009)

Bulletin de la Société Mathématique de France

We construct new birational maps between quadrics over a field. The maps apply to several types of quadratic forms, including Pfister neighbors, neighbors of multiples of a Pfister form, and half-neighbors. One application is to determine which quadrics over a field are ruled (that is, birational to the projective line times some variety) in a larger range of dimensions. We describe ruledness completely for quadratic forms of odd dimension at most 17, even dimension at most 10, or dimension 14....

Birational transformations and values of the Riemann zeta-function

Carlo Viola (2003)

Journal de théorie des nombres de Bordeaux

In his proof of Apery’s theorem on the irrationality of ζ ( 3 ) , Beukers [B] introduced double and triple integrals of suitable rational functions yielding good sequences of rational approximations to ζ ( 2 ) and ζ ( 3 ) . Beukers’ method was subsequently improved by Dvornicich and Viola, by Hata, and by Rhin and Viola. We give here a survey of our recent results ([RV2] and [RV3]) on the irrationality measures of ζ ( 2 ) and ζ ( 3 ) based upon a new algebraic method involving birational transformations and permutation groups...

Block Factorization of Hankel Matrices and Euclidean Algorithm

S. Belhaj (2010)

Mathematical Modelling of Natural Phenomena

It is shown that a real Hankel matrix admits an approximate block diagonalization in which the successive transformation matrices are upper triangular Toeplitz matrices. The structure of this factorization was first fully discussed in [1]. This approach is extended to obtain the quotients and the remainders appearing in the Euclidean algorithm applied to two polynomials u(x) and v(x) of degree n and m, respectively, whith m < ...

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