Geometry of Continued Fractions

For different subjects contributed to this book, the author was awarded a Fellowship of the City of Paris (France), a Lise Meitner Fellowship (Austria) and the Moscow Mathematical Society Prize (Russia).

Preface.- Introduction.- Part 1. Regular continued fractions: Chapter 1. Classical notions and definitions.- Chapter 2. On integer geometry.- Chapter 3. Geometry of regular continued fractions.- Chapter 4. Complete invariant of integer angles.- Chapter 5. Integer trigonometry for integer angles.- Chapter 6. Integer angles of integer triangles.- Chapter 7. Continued fractions and SL(2; Z) conjugacy classes. Elements of Gauss Reduction Theory. Markoff spectrum.- Chapter 8. Lagrange theorem.- Chapter 9. Gauss-Kuzmin statistics.- Chapter 10. Geometric approximation aspects.- Chapter 11. Geometry of continued fractions with real elements and the second Kepler law.- Chapter 12. Integer angles of polygons and global relations to toric singularities.- Part 2. Klein polyhedra: Chapter 13. Basic notions and definitions of multidimensional integer geometry.- Chapter 14. On empty simplices, pyramids, parallelepipeds.- Chapter 15. Multidimensional continued fractions in the sense of Klein.- Chapter16. Dirichlet groups and lattice reduction.- Chapter 17. Periodicity of Klein polyhedra. Generalization of Lagrange theorem.- Chapter 18. Multidimensional Gauss-Kuzmin statistics.- Chapter 19. On construction of multidimensional continued fractions.- Chapter 20. Gauss Reduction in higher dimensions.- Chapter 21. Decomposable forms. Relation to Littlewood and Oppenheim conjectures.- Chapter 22. Approximation of maximal commutative subgroups.- Chapter 23. Other generalizations of continued fractions.- Bibliography .

"Throughout the book many theorems are accompanied by constructive algorithms. Due to its rich content and connections to several parts of mathematics this volume will be of interest to graduate students and researchers not only in number theory and discrete geometry." (C. Baxa, Monatshefte für Mathematik, Vo. 180, 2016)

"Karpenkov ... begins with a distinctive treatment of continued fraction foundations emphasizing lattice geometry. One-dimensional continued fractions connect to two-dimensional lattices--very apt for illustration. ... Summing Up: Recommended. Upper-division undergraduates through researchers/faculty." (D. V. Feldman, Choice, Vol. 51 (10), June, 2014)

"The book is well written and is easy to read and navigate. ... The book features a number of helpful illustrations and tables, a detailed index, and a large bibliography.This text is likely to become a valuable resource for researchers and students interested in discrete geometry and Diophantine approximations, as well as their rich interplay and many connections." (Lenny Fukshansky, zbMATH, Vol. 1297, 2014)