Author: Robert M. Guralnick
Publisher: American Mathematical Soc.
ISBN: 9780821864951
Category : Mathematics
Languages : en
Pages : 100
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Book Description
In 1923 Schur considered the problem of which polynomials $f\in\mathbb{Z}[X]$ induce bijections on the residue fields $\mathbb{Z}/p\mathbb{Z}$ for infinitely many primes $p$. His conjecture, that such polynomials are compositions of linear and Dickson polynomials, was proved by M. Fried in 1970. Here we investigate the analogous question for rational functions, and also we allow the base field to be any number field. As a result, there are many more rational functions for which the analogous property holds. The new infinite series come from rational isogenies or endomorphisms of elliptic curves. Besides them, there are finitely many sporadic examples which do not fit in any of the series we obtain. The Galois theoretic translation, based on Chebotarev's density theorem, leads to a certain property of permutation groups, called exceptionality. One can reduce to primitive exceptional groups. While it is impossible to describe explicitly all primitive exceptional permutation groups, we provide certain reduction results, and obtain a classification in the almost simple case. The fact that these permutation groups arise as monodromy groups of covers of Riemann spheres $f:\mathbb{P}^1\to\mathbb{P}^1$, where $f$ is the rational function we investigate, provides genus $0$ systems. These are generating systems of permutation groups with a certain combinatorial property. This condition, combined with the classification and reduction results of exceptional permutation groups, eventually gives a precise geometric classification of possible candidates of rational functions which satisfy the arithmetic property from above. Up to this point, we make frequent use of the classification of the finite simple groups. Except for finitely many cases, these remaining candidates are connected to isogenies or endomorphisms of elliptic curves. Thus we use results about elliptic curves, modular curves, complex multiplication, and the techniques used in the inverse regular Galois problem to settle these finer arithmetic questions.
Author: Robert M. Guralnick
Publisher: American Mathematical Soc.
ISBN: 0821832883
Category : Mathematics
Languages : en
Pages : 96
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Book Description
Investigates the analogous question for rational functions. This book describes the Galois theoretic translation, based on Chebotarev's density theorem, leads to a certain property of permutation groups, called exceptionality.
Author: Ricardo Donato Salvatore
Publisher:
ISBN: 9781470403713
Category : Algebraic fields
Languages : en
Pages : 96
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Book Description
Investigates the analogous question for rational functions. This book describes the Galois theoretic translation, based on Chebotarev's density theorem, leads to a certain property of permutation groups, called exceptionality.
Author: R.W. Carter
Publisher: Springer Science & Business Media
ISBN: 9401153086
Category : Mathematics
Languages : en
Pages : 388
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Book Description
This volume contains 19 articles written by speakers at the Advanced Study Institute on 'Modular representations and subgroup structure of al gebraic groups and related finite groups' held at the Isaac Newton Institute, Cambridge from 23rd June to 4th July 1997. We acknowledge with gratitude the financial support given by the NATO Science Committee to enable this ASI to take place. Generous financial support was also provided by the European Union. We are also pleased to acknowledge funds given by EPSRC to the Newton Institute which were used to support the meeting. It is a pleasure to thank the Director of the Isaac Newton Institute, Professor Keith Moffatt, and the staff of the Institute for their dedicated work which did so much to further the success of the meeting. The editors wish to thank Dr. Ross Lawther and Dr. Nick Inglis most warmly for their help in the production of this volume. Dr. Lawther in particular made an invaluable contribution in preparing the volume for submission to the publishers. Finally we wish to thank the distinguished speakers at the ASI who agreed to write articles for this volume based on their lectures at the meet ing. We hope that the volume will stimulate further significant advances in the theory of algebraic groups.
Author: Chris Christensen
Publisher: Springer Science & Business Media
ISBN: 3642184871
Category : Mathematics
Languages : en
Pages : 778
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Book Description
Proceedings of the Conference on Algebra and Algebraic Geometry with Applications, July 19 – 26, 2000, at Purdue University to honor Professor Shreeram S. Abhyankar on the occasion of his seventieth birthday. Eighty-five of Professor Abhyankar's students, collaborators, and colleagues were invited participants. Sixty participants presented papers related to Professor Abhyankar's broad areas of mathematical interest. Sessions were held on algebraic geometry, singularities, group theory, Galois theory, combinatorics, Drinfield modules, affine geometry, and the Jacobian problem. This volume offers an outstanding collection of papers by expert authors.
Author: Valentin Poenaru
Publisher: American Mathematical Soc.
ISBN: 0821834606
Category : Mathematics
Languages : en
Pages : 104
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Book Description
Shows that at the cost of replacing $V DEGREES3$ by $V_h DEGREES3 = \{V DEGREES3$ with very many holes $\}$, we can always find representations $X DEGREES2 \stackrel {f} {\rightarrow} V DEGREES3$ with $X DEGREES2$ locally finite and almost-arborescent, with $\Psi (f)=\Phi (f)$, and with the ope
Author: Ola Bratteli
Publisher: American Mathematical Soc.
ISBN: 0821834916
Category : Mathematics
Languages : en
Pages : 202
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Book Description
Part A. Representation theory Part B. Numerical AF-invariants Bibliography List of figures List of tables List of terms and symbols.
Author: Benoît Mselati
Publisher: American Mathematical Soc.
ISBN: 0821835092
Category : Mathematics
Languages : en
Pages : 146
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Book Description
Concerned with the nonnegative solutions of $\Delta u = u^2$ in a bounded and smooth domain in $\mathbb{R}^d$, this title intends to prove that they are uniquely determined by their fine trace on the boundary as defined in [DK98a], answering a major open question of [Dy02].
Author: Aleksandr I︠U︡rʹevich Olʹshanskiĭ
Publisher: American Mathematical Soc.
ISBN: 0821835130
Category : Mathematics
Languages : en
Pages : 150
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Book Description
For every finitely generated recursively presented group $\mathcal G$ we construct a finitely presented group $\mathcal H$ containing $\mathcal G$ such that $\mathcal G$ is (Frattini) embedded into $\mathcal H$ and the group $\mathcal H$ has solvable conjugacy problem if and only if $\mathcal G$ has solvable conjugacy problem.
Author: Claus Mokler
Publisher: American Mathematical Soc.
ISBN: 082183648X
Category : Mathematics
Languages : en
Pages : 104
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Book Description
By an easy generalization of the Tannaka-Krein reconstruction we associate to the category of admissible representations of the category ${\mathcal O}$ of a Kac-Moody algebra, and its category of admissible duals, a monoid with a coordinate ring. The Kac-Moody group is the Zariski open dense unit group of this monoid. The restriction of the coordinate ring to the Kac-Moody group is the algebra of strongly regular functions introduced by V. Kac and D. Peterson. This monoid has similar structural properties as a reductive algebraic monoid. In particular it is unit regular, its idempotents related to the faces of the Tits cone. It has Bruhat and Birkhoff decompositions. The Kac-Moody algebra is isomorphic to the Lie algebra of this monoid.
