Discrete Integrable Systems
QRT Maps and Elliptic Surfaces
Johannes J. Duistermaat
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ISSN 1439-7382
Springer New York Dordrecht Heidelberg London
© Springer Science+Business Media, LLC 2010
Library of Congress Control Number:
e-ISBN 978-0-387-72923-7
ISBN 978-1-4419-7116-6
Johannes J. Duistermaat (deceased, March 2010)
2010934229
DOI 10.1007/978-0-387-72923-7
Contents
Preface ............................................................ vii
1 The QRT Map ................................................. 1
1.1 The Rational Formula for the QRT Map ........................ 1
1.2 Indeterminacy of the QRT Map ............................... 3
1.3 Reconstruction ............................................. 4
2 The Pencil of Biquadratic Curves in P
1
× P
1
...................... 9
2.1 Complex Analytic Geometry ................................. 10
2.2 Complex Projective Varieties ................................. 28
2.3 Elliptic Curves ............................................. 33
2.4 Biquadratic Curves ......................................... 49
2.5 The QRT Mapping on a Smooth Biquadratic Curve .............. 60
2.6 Real Points ................................................ 74
3 The QRT surface ............................................... 85
3.1 The surface in P
1
×(P
1
×P
1
) ................................ 86
3.2 Blowing Up ............................................... 93
3.3 Blowing Up P
1
×P
1
at the Base Points ........................105
3.4 The QRT Map on the QRT Surface ............................119
4 Cubic Curves in the Projective Plane .............................129
4.1 From P
1
×P
1
to P
2
and Back ................................129
4.2 Manin Transformations ......................................134
4.3 Manin QRT Automorphisms .................................138
4.4 Aronhold’s Invariants .......................................143
4.5 Pencils of Cubic Curves with Only One Base Point ..............148
5 The Action of the QRT Map on Homology ........................157
5.1 The Action of the QRT Map on Homology Classes ..............157
5.2 QRT Transformations of Finite Order ..........................164
6 Elliptic Surfaces ...............................................179
6.1 Fibrations .................................................179
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