نتایج جستجو برای: convexconcave elliptic

تعداد نتایج: 32164  

پایان نامه :0 1371

the treatment of in completely formed pulpless teeth has presented considrable problems. these teeth have wide open apexes and the walls of the root canal diverge toward the apical tissues. mechanical preparation cannot be done in the normal manner beacause of the large initial size and the taper of apical part of the canal , a mechanical stop cannot be produced at the apex of the canal and , t...

2003
HJALMAR ROSENGREN Richard Askey

Elliptic 6j-symbols first appeared in connection with solvable models of statistical mechanics. They include many interesting limit cases, such as quantum 6j-symbols (or q-Racah polynomials) and Wilson’s biorthogonal 10W9 functions. We give an elementary construction of elliptic 6j-symbols, which immediately implies several of their main properties. As a consequence, we obtain a new algebraic i...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز 1382

در این پایان نامه به منظور تدوین نرم افزاری جهت طراحی چرخ پمپ سانتریفوژ، مقایسه ای بین نتایج حاصل از روشهای طراحی با نمونه های واقعی صورت گرفته است. برای طراحی چرخ از دو روش کلاسیک استپانوف، اولر و یک روش پیشنهادی جدید، که ترکیبی از دو روش کلاسیک استپانوف و لبانوف می باشد، استفاده شده است . همچنین برای کنترل تخمین تعداد پره ها، به جای روشهای معمول از تخمین ضریب لغزش و محاسبه آن از سه تئوری بوزم...

1995
A. Grassi

This work was initially motivated by Miranda’s work on elliptic Weierstrass threefolds. An elliptic variety is a complex (irreducible and reduced) projective variety together with a morphism π : X → S whose fiber over a general point is a smooth elliptic curve. For example, if the elliptic fibration has a section, X can be locally expressed as a hypersurface [De]. This is called the Weierstrass...

Journal: :journal of linear and topological algebra (jlta) 0
f yaghoobi department of mathemetics, college of science, hamedan branch, islamic azad university, hamedan, iran j shamshiri department of mathematics, mashhad branch, islamic azad university, mashhad, iran

this study concerns the existence and multiplicity of positive weak solutions for a class ofsemilinear elliptic systems with nonlinear boundary conditions. our results is depending onthe local minimization method on the nehari manifold and some variational techniques. alsoby using mountain pass lemma, we establish the existence of at least one solution withpositive energy.

2008
Satoshi Tsujimoto Alexei Zhedanov

We construct new elliptic solutions of the qd-algorithm. These solutions can be interpreted as elliptic solutions of the discrete-time Toda chain as well. As a by-product, we obtain new explicit orthogonal and biorthogonal polynomials in terms of the elliptic hypergeometric function 3G2(z). Their recurrence coefficients are expressed in terms of the elliptic functions. 1991 Mathematics Subject ...

Journal: :IEICE Transactions 2006
Jumpei Uchida Nozomu Togawa Masao Yanagisawa Tatsuo Ohtsuki

Elliptic curve cryptosystems are expected to be a next standard of public-key cryptosystems. A security level of elliptic curve cryptosystems depends on a difficulty of a discrete logarithm problem on elliptic curves. The security level of a elliptic curve cryptosystem which has a public-key of 160-bit is equivalent to that of a RSA system which has a public-key of 1024-bit. We propose an ellip...

1999
JUNG HEE CHEON HWAN JOON KIM SANG GEUN HAHN

The Elliptic Curve Discrete Logarithm Problem(ECDLP) is known to be an exponential time problem except the cases of smooth curves, supersingular curves and anomalous curves. Recently, several new methods to solve ECDLP on a prime eld were proposed. All of them try to solve ECDLP on a prime eld by lifting a given elliptic curve to low rank elliptic curves de ned over the rationals. In this exten...

1998
Tetsuya Izu Jun Kogure Masayuki Noro Kazuhiro Yokoyama

The security of elliptic curve cryptosystem depends on the choice of an elliptic curve on which cryptographic operations are performed. Schoof’s algorithm is used to define a secure elliptic curve, as it can compute the number of rational points on a randomly selected elliptic curve defined over a finite field. By realizing efficient combination of several improvements, such as Atkin-Elkies’s m...

2008
Igor Nikolaev

To every non-singular elliptic curve (complex torus) we assign a C∗algebra Tθ = {u, v | vu = e uv} known as noncommutative torus. It is shown that morphisms of elliptic curves generate Morita equivalence of the corresponding noncommutative tori. Real number θ we call projective curvature attached to the elliptic curve. It is proved that projective curvatures of isomorphic elliptic curves are mo...

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