Real Non-Abelian Mixed Hodge Structures for Quasi-Projective Varieties: Formality and Splitting

Real Non-Abelian Mixed Hodge Structures for Quasi-Projective Varieties: Formality and Splitting

Author: J. P. Pridham

Publisher: American Mathematical Soc.

Published: 2016-09-06

Total Pages: 178

ISBN-13: 1470419815

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The author defines and constructs mixed Hodge structures on real schematic homotopy types of complex quasi-projective varieties, giving mixed Hodge structures on their homotopy groups and pro-algebraic fundamental groups. The author also shows that these split on tensoring with the ring R[x] equipped with the Hodge filtration given by powers of (x−i), giving new results even for simply connected varieties. The mixed Hodge structures can thus be recovered from the Gysin spectral sequence of cohomology groups of local systems, together with the monodromy action at the Archimedean place. As the basepoint varies, these structures all become real variations of mixed Hodge structure.


Book Synopsis Real Non-Abelian Mixed Hodge Structures for Quasi-Projective Varieties: Formality and Splitting by : J. P. Pridham

Download or read book Real Non-Abelian Mixed Hodge Structures for Quasi-Projective Varieties: Formality and Splitting written by J. P. Pridham and published by American Mathematical Soc.. This book was released on 2016-09-06 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The author defines and constructs mixed Hodge structures on real schematic homotopy types of complex quasi-projective varieties, giving mixed Hodge structures on their homotopy groups and pro-algebraic fundamental groups. The author also shows that these split on tensoring with the ring R[x] equipped with the Hodge filtration given by powers of (x−i), giving new results even for simply connected varieties. The mixed Hodge structures can thus be recovered from the Gysin spectral sequence of cohomology groups of local systems, together with the monodromy action at the Archimedean place. As the basepoint varies, these structures all become real variations of mixed Hodge structure.


Abelian Properties of Anick Spaces

Abelian Properties of Anick Spaces

Author: Brayton Gray

Publisher: American Mathematical Soc.

Published: 2017-02-20

Total Pages: 111

ISBN-13: 1470423081

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Anick spaces are closely connected with both EHP sequences and the study of torsion exponents. In addition they refine the secondary suspension and enter unstable periodicity. This work describes their -space properties as well as universal properties. Techniques include a new kind on Whitehead product defined for maps out of co-H spaces, calculations in an additive category that lies between the unstable category and the stable category, and a controlled version of the extension theorem of Gray and Theriault (Geom. Topol. 14 (2010), no. 1, 243–275).


Book Synopsis Abelian Properties of Anick Spaces by : Brayton Gray

Download or read book Abelian Properties of Anick Spaces written by Brayton Gray and published by American Mathematical Soc.. This book was released on 2017-02-20 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anick spaces are closely connected with both EHP sequences and the study of torsion exponents. In addition they refine the secondary suspension and enter unstable periodicity. This work describes their -space properties as well as universal properties. Techniques include a new kind on Whitehead product defined for maps out of co-H spaces, calculations in an additive category that lies between the unstable category and the stable category, and a controlled version of the extension theorem of Gray and Theriault (Geom. Topol. 14 (2010), no. 1, 243–275).


Maximal Cohen-Macaulay Modules Over Non-Isolated Surface Singularities and Matrix Problems

Maximal Cohen-Macaulay Modules Over Non-Isolated Surface Singularities and Matrix Problems

Author: Igor Burban

Publisher: American Mathematical Soc.

Published: 2017-07-13

Total Pages: 114

ISBN-13: 1470425378

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In this article the authors develop a new method to deal with maximal Cohen–Macaulay modules over non–isolated surface singularities. In particular, they give a negative answer on an old question of Schreyer about surface singularities with only countably many indecomposable maximal Cohen–Macaulay modules. Next, the authors prove that the degenerate cusp singularities have tame Cohen–Macaulay representation type. The authors' approach is illustrated on the case of k as well as several other rings. This study of maximal Cohen–Macaulay modules over non–isolated singularities leads to a new class of problems of linear algebra, which the authors call representations of decorated bunches of chains. They prove that these matrix problems have tame representation type and describe the underlying canonical forms.


Book Synopsis Maximal Cohen-Macaulay Modules Over Non-Isolated Surface Singularities and Matrix Problems by : Igor Burban

Download or read book Maximal Cohen-Macaulay Modules Over Non-Isolated Surface Singularities and Matrix Problems written by Igor Burban and published by American Mathematical Soc.. This book was released on 2017-07-13 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this article the authors develop a new method to deal with maximal Cohen–Macaulay modules over non–isolated surface singularities. In particular, they give a negative answer on an old question of Schreyer about surface singularities with only countably many indecomposable maximal Cohen–Macaulay modules. Next, the authors prove that the degenerate cusp singularities have tame Cohen–Macaulay representation type. The authors' approach is illustrated on the case of k as well as several other rings. This study of maximal Cohen–Macaulay modules over non–isolated singularities leads to a new class of problems of linear algebra, which the authors call representations of decorated bunches of chains. They prove that these matrix problems have tame representation type and describe the underlying canonical forms.


Exotic Cluster Structures on $SL_n$: The Cremmer-Gervais Case

Exotic Cluster Structures on $SL_n$: The Cremmer-Gervais Case

Author: M. Gekhtman

Publisher: American Mathematical Soc.

Published: 2017-02-20

Total Pages: 94

ISBN-13: 1470422581

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This is the second paper in the series of papers dedicated to the study of natural cluster structures in the rings of regular functions on simple complex Lie groups and Poisson–Lie structures compatible with these cluster structures. According to our main conjecture, each class in the Belavin–Drinfeld classification of Poisson–Lie structures on corresponds to a cluster structure in . The authors have shown before that this conjecture holds for any in the case of the standard Poisson–Lie structure and for all Belavin–Drinfeld classes in , . In this paper the authors establish it for the Cremmer–Gervais Poisson–Lie structure on , which is the least similar to the standard one.


Book Synopsis Exotic Cluster Structures on $SL_n$: The Cremmer-Gervais Case by : M. Gekhtman

Download or read book Exotic Cluster Structures on $SL_n$: The Cremmer-Gervais Case written by M. Gekhtman and published by American Mathematical Soc.. This book was released on 2017-02-20 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second paper in the series of papers dedicated to the study of natural cluster structures in the rings of regular functions on simple complex Lie groups and Poisson–Lie structures compatible with these cluster structures. According to our main conjecture, each class in the Belavin–Drinfeld classification of Poisson–Lie structures on corresponds to a cluster structure in . The authors have shown before that this conjecture holds for any in the case of the standard Poisson–Lie structure and for all Belavin–Drinfeld classes in , . In this paper the authors establish it for the Cremmer–Gervais Poisson–Lie structure on , which is the least similar to the standard one.


Applications of Polyfold Theory I: The Polyfolds of Gromov-Witten Theory

Applications of Polyfold Theory I: The Polyfolds of Gromov-Witten Theory

Author: H. Hofer

Publisher: American Mathematical Soc.

Published: 2017-07-13

Total Pages: 218

ISBN-13: 1470422034

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In this paper the authors start with the construction of the symplectic field theory (SFT). As a general theory of symplectic invariants, SFT has been outlined in Introduction to symplectic field theory (2000), by Y. Eliashberg, A. Givental and H. Hofer who have predicted its formal properties. The actual construction of SFT is a hard analytical problem which will be overcome be means of the polyfold theory due to the present authors. The current paper addresses a significant amount of the arising issues and the general theory will be completed in part II of this paper. To illustrate the polyfold theory the authors use the results of the present paper to describe an alternative construction of the Gromov-Witten invariants for general compact symplectic manifolds.


Book Synopsis Applications of Polyfold Theory I: The Polyfolds of Gromov-Witten Theory by : H. Hofer

Download or read book Applications of Polyfold Theory I: The Polyfolds of Gromov-Witten Theory written by H. Hofer and published by American Mathematical Soc.. This book was released on 2017-07-13 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper the authors start with the construction of the symplectic field theory (SFT). As a general theory of symplectic invariants, SFT has been outlined in Introduction to symplectic field theory (2000), by Y. Eliashberg, A. Givental and H. Hofer who have predicted its formal properties. The actual construction of SFT is a hard analytical problem which will be overcome be means of the polyfold theory due to the present authors. The current paper addresses a significant amount of the arising issues and the general theory will be completed in part II of this paper. To illustrate the polyfold theory the authors use the results of the present paper to describe an alternative construction of the Gromov-Witten invariants for general compact symplectic manifolds.


Rationality Problem for Algebraic Tori

Rationality Problem for Algebraic Tori

Author: Akinari Hoshi

Publisher: American Mathematical Soc.

Published: 2017-07-13

Total Pages: 215

ISBN-13: 1470424096

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The authors give the complete stably rational classification of algebraic tori of dimensions and over a field . In particular, the stably rational classification of norm one tori whose Chevalley modules are of rank and is given. The authors show that there exist exactly (resp. , resp. ) stably rational (resp. not stably but retract rational, resp. not retract rational) algebraic tori of dimension , and there exist exactly (resp. , resp. ) stably rational (resp. not stably but retract rational, resp. not retract rational) algebraic tori of dimension . The authors make a procedure to compute a flabby resolution of a -lattice effectively by using the computer algebra system GAP. Some algorithms may determine whether the flabby class of a -lattice is invertible (resp. zero) or not. Using the algorithms, the suthors determine all the flabby and coflabby -lattices of rank up to and verify that they are stably permutation. The authors also show that the Krull-Schmidt theorem for -lattices holds when the rank , and fails when the rank is ...


Book Synopsis Rationality Problem for Algebraic Tori by : Akinari Hoshi

Download or read book Rationality Problem for Algebraic Tori written by Akinari Hoshi and published by American Mathematical Soc.. This book was released on 2017-07-13 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors give the complete stably rational classification of algebraic tori of dimensions and over a field . In particular, the stably rational classification of norm one tori whose Chevalley modules are of rank and is given. The authors show that there exist exactly (resp. , resp. ) stably rational (resp. not stably but retract rational, resp. not retract rational) algebraic tori of dimension , and there exist exactly (resp. , resp. ) stably rational (resp. not stably but retract rational, resp. not retract rational) algebraic tori of dimension . The authors make a procedure to compute a flabby resolution of a -lattice effectively by using the computer algebra system GAP. Some algorithms may determine whether the flabby class of a -lattice is invertible (resp. zero) or not. Using the algorithms, the suthors determine all the flabby and coflabby -lattices of rank up to and verify that they are stably permutation. The authors also show that the Krull-Schmidt theorem for -lattices holds when the rank , and fails when the rank is ...


Special Values of the Hypergeometric Series

Special Values of the Hypergeometric Series

Author: Akihito Ebisu

Publisher: American Mathematical Soc.

Published: 2017-07-13

Total Pages: 96

ISBN-13: 1470425335

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In this paper, the author presents a new method for finding identities for hypergeoemtric series, such as the (Gauss) hypergeometric series, the generalized hypergeometric series and the Appell-Lauricella hypergeometric series. Furthermore, using this method, the author gets identities for the hypergeometric series and shows that values of at some points can be expressed in terms of gamma functions, together with certain elementary functions. The author tabulates the values of that can be obtained with this method and finds that this set includes almost all previously known values and many previously unknown values.


Book Synopsis Special Values of the Hypergeometric Series by : Akihito Ebisu

Download or read book Special Values of the Hypergeometric Series written by Akihito Ebisu and published by American Mathematical Soc.. This book was released on 2017-07-13 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, the author presents a new method for finding identities for hypergeoemtric series, such as the (Gauss) hypergeometric series, the generalized hypergeometric series and the Appell-Lauricella hypergeometric series. Furthermore, using this method, the author gets identities for the hypergeometric series and shows that values of at some points can be expressed in terms of gamma functions, together with certain elementary functions. The author tabulates the values of that can be obtained with this method and finds that this set includes almost all previously known values and many previously unknown values.


New Foundations for Geometry: Two Non-Additive Languages for Arithmetical Geometry

New Foundations for Geometry: Two Non-Additive Languages for Arithmetical Geometry

Author: Shai M. J. Haran

Publisher: American Mathematical Soc.

Published: 2017-02-20

Total Pages: 202

ISBN-13: 147042312X

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To view the abstract go to http://www.ams.org/books/memo/1166.


Book Synopsis New Foundations for Geometry: Two Non-Additive Languages for Arithmetical Geometry by : Shai M. J. Haran

Download or read book New Foundations for Geometry: Two Non-Additive Languages for Arithmetical Geometry written by Shai M. J. Haran and published by American Mathematical Soc.. This book was released on 2017-02-20 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: To view the abstract go to http://www.ams.org/books/memo/1166.


Proof of the 1-Factorization and Hamilton Decomposition Conjectures

Proof of the 1-Factorization and Hamilton Decomposition Conjectures

Author: Béla Csaba

Publisher: American Mathematical Soc.

Published: 2016-10-05

Total Pages: 164

ISBN-13: 1470420252

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In this paper the authors prove the following results (via a unified approach) for all sufficiently large n: (i) [1-factorization conjecture] Suppose that n is even and D≥2⌈n/4⌉−1. Then every D-regular graph G on n vertices has a decomposition into perfect matchings. Equivalently, χ′(G)=D. (ii) [Hamilton decomposition conjecture] Suppose that D≥⌊n/2⌋. Then every D-regular graph G on n vertices has a decomposition into Hamilton cycles and at most one perfect matching. (iii) [Optimal packings of Hamilton cycles] Suppose that G is a graph on n vertices with minimum degree δ≥n/2. Then G contains at least regeven(n,δ)/2≥(n−2)/8 edge-disjoint Hamilton cycles. Here regeven(n,δ) denotes the degree of the largest even-regular spanning subgraph one can guarantee in a graph on n vertices with minimum degree δ. (i) was first explicitly stated by Chetwynd and Hilton. (ii) and the special case δ=⌈n/2⌉ of (iii) answer questions of Nash-Williams from 1970. All of the above bounds are best possible.


Book Synopsis Proof of the 1-Factorization and Hamilton Decomposition Conjectures by : Béla Csaba

Download or read book Proof of the 1-Factorization and Hamilton Decomposition Conjectures written by Béla Csaba and published by American Mathematical Soc.. This book was released on 2016-10-05 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper the authors prove the following results (via a unified approach) for all sufficiently large n: (i) [1-factorization conjecture] Suppose that n is even and D≥2⌈n/4⌉−1. Then every D-regular graph G on n vertices has a decomposition into perfect matchings. Equivalently, χ′(G)=D. (ii) [Hamilton decomposition conjecture] Suppose that D≥⌊n/2⌋. Then every D-regular graph G on n vertices has a decomposition into Hamilton cycles and at most one perfect matching. (iii) [Optimal packings of Hamilton cycles] Suppose that G is a graph on n vertices with minimum degree δ≥n/2. Then G contains at least regeven(n,δ)/2≥(n−2)/8 edge-disjoint Hamilton cycles. Here regeven(n,δ) denotes the degree of the largest even-regular spanning subgraph one can guarantee in a graph on n vertices with minimum degree δ. (i) was first explicitly stated by Chetwynd and Hilton. (ii) and the special case δ=⌈n/2⌉ of (iii) answer questions of Nash-Williams from 1970. All of the above bounds are best possible.


The $abc$-Problem for Gabor Systems

The $abc$-Problem for Gabor Systems

Author: Xin-Rong Dai

Publisher: American Mathematical Soc.

Published: 2016-10-05

Total Pages: 99

ISBN-13: 1470420155

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A longstanding problem in Gabor theory is to identify time-frequency shifting lattices aZ×bZ and ideal window functions χI on intervals I of length c such that {e−2πinbtχI(t−ma): (m,n)∈Z×Z} are Gabor frames for the space of all square-integrable functions on the real line. In this paper, the authors create a time-domain approach for Gabor frames, introduce novel techniques involving invariant sets of non-contractive and non-measure-preserving transformations on the line, and provide a complete answer to the above abc-problem for Gabor systems.


Book Synopsis The $abc$-Problem for Gabor Systems by : Xin-Rong Dai

Download or read book The $abc$-Problem for Gabor Systems written by Xin-Rong Dai and published by American Mathematical Soc.. This book was released on 2016-10-05 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: A longstanding problem in Gabor theory is to identify time-frequency shifting lattices aZ×bZ and ideal window functions χI on intervals I of length c such that {e−2πinbtχI(t−ma): (m,n)∈Z×Z} are Gabor frames for the space of all square-integrable functions on the real line. In this paper, the authors create a time-domain approach for Gabor frames, introduce novel techniques involving invariant sets of non-contractive and non-measure-preserving transformations on the line, and provide a complete answer to the above abc-problem for Gabor systems.