4,463 research outputs found
Modular Curves Of Genus 2
We prove that there is only a finite number of genus 2 curves C defined over
Q such that there exists a nonconstant morphism pi:X_1(N) --->C defined over Q
and the jacobian of C, J(C), is a Q-factor of the new part of the jacobian of
X_1(N), J_1(N)^{new}. Moreover, we prove that there are only 149 genus two
curves of this kind with the additional requeriment that their jacobians are
Q-simple. We determine the corresponding newforms and present equations for all
these curves
Covering techniques and rational points on some genus 5 curves
We describe a method that allows, under some hypotheses, to compute all the
rational points of some genus 5 curves defined over a number field. This method
is used to solve some arithmetic problems that remained open.Comment: Contemporary Mathematics AMS, to appea
Study of the Effect of Hot Rolling Processing Parameters on the Variability of HSLA Steels
The effect of different hot mill processing parameters and their influence on the variability of mechanical properties of HSLA steels has been studied. This work presents an analysis of the relative contribution of the different hot mill processing parameters to the variability of HSLA steels. The experimental design includes variation of Reheating, Roughing, Finishing, and Coiling temperatures, as well as Cooling Rate through the austenite to ferrite transformation, and from coiling to room temperature. The variation in finishing and coiling temperature results in an average variation of 12% in mechanical properties. The variation of the cooling rate, through the austenite to ferrite transformation, and from coiling to room temperature, has the largest impact on the variability of microstructure and properties. A correlation between the various microstructural features, dislocation densities and precipitation behavior, with mechanical properties is presented
On symmetric square values of quadratic polynomials
We prove that there does not exist a non-square quadratic polynomial with
integer coefficients and an axis of symmetry which takes square values for N
consecutive integers for N=7 or N >= 9. At the opposite, if N <= 6 or N=8 there
are infinitely many
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